UPDATED!
I switched to a 12volt relay, added a project box and upgraded the auto relay off recipe. Joy.

Hi.
I'm a bit ashamed of this hack, since it mostly uses existing technologies, but I shall post it anyway for all of the glory and cash rewards.

My garage opener remote recently passed away with very little notice. This was frustrating because I make it clear to any electronics I adopt that they are to give me ample warning if they are on their way out. No such luck. This remote was a rebel and certainly not a gentleman.

I needed a replacement, naturally. Universal remotes are fine, but there are a few limitations which I'm not keen on:

1. Limited range. I have to be within 50 feet or so of my house to use them. What if I want to let a family member in who is locked out in the frigid 90 degree Florida weather, or open the house for the dog walker (if I had a dog walker), or make all of my belongings available to the crooks who live in my neighborhood for insurance fraud purposes? Right.

2. Remote batteries die. I don't like death. It makes me uncomfortable. iPhone can be recharged anywhere and everywhere, even in the car (imagine that!)

3. Why carry more devices around than necessary? These smart phones are pretty damn smart these days. They should be doing more for us, like massages and walking our dogs. Also, opening our garages or other entry-ways. Plus garage remotes weigh about 45 lbs. Not cool.

4. Physical buttons are a point of failure. Chances are, I'll have to replace an old-school garage remote again after a few million uses. Who needs that kind of uncertainty in their life? No sir, a capacitive (really spell check, "capacitive" is not in your dictionary in this modern age?) touch screen is superior in my book! Dare I say it has billions of touches in store before the glass wears through and liquid crystal toxins seep into my fingers!

I'll admit that point 4 was a weak one, but I like things in fours, which is why I've removed both of my thumbs (see pics).
I can type anything I want here, can't I?
Whhheeeeeeeeeeeeeeeeeeeeeeee! Wooooooords!!!!!

Continue on to see the hows and whats, friends!

Step 1: Belkin Wemo Wifi Outlet (or, Finding Wemo)

Here's the first half of the magic, kids.

These Belkin Wifi outlets are great. They can be controlled from your phone, from anywhere. They cost about $50 at Apple, Target, etc. A bit steep for turning a light on, but I found it a justifiable cost for this use. Certainly there are many other ways to do this same thing (Raspberry Pi, Arduino, laptop, unused cellphone), but this was easy and took about a half hour once I had the supplies in hand.

Setup is really easy. The Wemo connects itself to your home Wifi router and becomes accessible from your phone via their app.

The coolest part is that IFTTT (If This Then That) now supports the Wemo! If you're not familiar with this, then I'll tell you about that .(see what I did there?)

Visit IFTTT.com.It's a free service which connects many different data sources together based on simple rules called recipes. It can even control certain hardware, like this Belkin switch or the Philips LED Hue light bulbs.

More on IFTTT later.

Step 2: The Power

Luckily there is an extra power outlet on the ceiling next to my opener. Perhaps this is how they all are, but I'm going to pretend that I'm lucky to feel better about myself. Also, I have a gambling addiction.

The black cord you see plugged into the Wemo is just a chopped off old lamp cord. I'll show it's use in the next step, but PLEASE MAKE A NOTE OF IT! It needs to be of the type that can handle wall current (110 volts typically, or if in the UK something like 153,000 volts... i don't really know). You'll see why in a moment... turn the page.

Update:
I replaced this power cord with a 12 volt wall wart style transformer instead of a direct 110 volts. Made me feel better. Just need to get a picture of it up here.

Step 3: Switch It Up.

Now then, there comes a time in every young man's (woman's) life when he (she) must do some actual work. Booooo...

Here we see a Tyco Electronics 12 volt Mechanical relay switch. I got this at Radio Shack, but any relay switch which activates under 12 volts and has a normally open state will work. What does normally mean? Glad you asked.

These relay switches work in the following way:
1. Power is applied to an electromagnetic coil inside
2. a metal plate is drawn to the coil, which moves a bunch of metal contacts
3. Some contacts which were already touching (closed) become open, and some open ones become closed.

We want to use two of the normally open contacts, so that when power is applied, they will close and complete a circuit which we'll use to trigger the garage opener. Read on.

Note:
Is should be noted that the 12 volts is simply used here to close the magnetic circuit. This voltage DOES NOT and SHOULD NOT be passed into the garage door opener circuitry. That would likely break stuff. I can't be held responsible for the loss of your home! Mine is 300 square feet. I've got nothing to lose!

Note again:
I did go back and insulate the wires after taking the photo. You must do this to ensure no stray voltage gets out or shorts on the metal housing of the garage opener or someones face. Shrink wrap tubing or black electrical tape should do it. Also, zip tie this relay to a secure post somewhere, just like I didn't do here.

Step 4: Trigger Wires

I have connected the two yellow trigger wires to the same two screw terminals that connect to the manual garage opener button coming from my wall. Be sure they are yellow, since no other color will work. Yellow lets electrons flow best (none of that is true).

The color does not matter. Any wires will work for this step since it is only being used to close the circuit, just as the original wall button wiring does when pushed. I left the original wires there too so that the wall button still works.

I cannot speak to every opener type here, but this is my setup. Simple and clean. Tracing the wires from you wall mounted button is a good way to find out which terminals are the right ones.

Step 5: If This Then That!

So back to IFTTT.

It's a great free (for now) service based out of San Francisco that lets you set up simple rules (or Recipes) to trigger events, messages or actions.

I've set up a few easy ones, which let me trigger my Wemo any time IFTTT receives a text or voice mail from my phone number.
Here's the main recipe: https://ifttt.com/recipes/96423

It is important to note that I have chosen the Wemo action "Turn on then off". This allows the garage opener to activate, but then release, as if the physical wall button was being pressed. If the relay is left switched on, who knows what atrocities could occur!?

Really though, that wouldn't be safe. I accidentally left it switched on for an entire day, and it became fairly warm. For this reason, I added a few more rules which shut the Wemo off several times a day for safety. Read on.

Update:
I added one more rule to rule them all... a rule that says "you turn that junk on? Well I'm turning it the hell off, see!?"
This means that any time the Wemo is triggered on, IFTTT goes and turns it off. So I can use the Wemo app to open now without having to remember to turn off the relay too.

Surely there's a better way.

Step 6: Safety Last!

Here are the safety shutoff recipes on IFTTT.

I just ping the Wemo 4 times a day and tell it to turn off. This affects nothing negatively. If its already off, as it should be, it does nothing. It is not a toggle. At 3am, 6am, 3pm and 6pm my Wemo is told to turn off. Do more if you're paranoid like me.

If somehow I got drunk on chocolate and passed out on my phone with the Wemo app open and my tongue touching the "on" button, then one of these recipes would save my life, or at least save the relay from burning out eventually. Not much different than if I passed out and stuck to the wall in the garage with my tongue on the wall mounted button (button would like that too much).

Be sure that you do not set up any more Wemo based rules! IFTT only supports one Wemo right now, so if you try to add another rule thinking you're turning lights on in your house, it'll affect the garage Wemo. Don't do it!

Update:
Apparently IFTTT now supports multiple devices! Woohoo!
http://updates.ifttt.com/post/50125496053/belkin-wemo-multi-device-control

Step 7: Sucess, With One "C"!

I can now use Siri to text my house and open the garage.

I can now text my house the old fashioned way to open my garage.

I can now call my house to open my garage.

Notice it says "The Mansion". When you text or call iFTTT, they give you a number for their automation servers. I just entered that number in my contacts list as "The Mansion" so that I could say "Siri, text The Mansion and tell it to open my damn garage, now please!"

You can store the number as anything you want. Don't follow my advise. It isn't sound.

Thanks for reading!
I'll be figuring out a way to get out of my garage (phone isn't charged).