If you're clumsy like me and drop your phone onto a stone paver, you'll have to replace the digitizer screen (and possibly LCD).
Step 1: Assemble Materials
I have a small Phillips screwdriver and guitar pick but lack the small pry tool, so I opted for the new digitizer screen that came with a small set of tools. It included star and flathead drivers and a larger pry tool and suction tool I didn't use, but it also had precut adhesive that was nice since I don't have a roll of thin double sided tape.
If your LCD is damaged, or you damage it in the process of removing the broken digitizer (like I did), you'll want to pick up a replacement LCD as well. Sourced mine from ebay.
Step 2: Open Up the Phone
Remove the back cover by prying with your fingers or pry tool from the small access hole. The cover will pop right off
Remove battery and data cards.
Remove the 7 small Phillips screws (red arrows)
Gently run the pry tool around the entire perimeter between the middle housing and the front cover. You'll hear pops and clicks as the two separate. The middle housing will lift right up.
Step 3: Disconnect and Remove Circuit Board
There are 4 ribbon connectors and one small plug that need to be disconnected before the board is removed.
Three of the ribbon connectors have brown tabs. The illustrated one above has a white tab. Gently pick up on the tab and pull the ribbon out. Easy peasy!
The square chip (top center) of the digitizer has some adhesive holding it in place, so carefully separate it from the other ribbon. The circuit board should lift right out when everything's disconnected.
Step 4: Gently Heat the Adhesive and Remove Damaged Digitizer
I used my solder gun that has a small side port of heat, but a heat gun will work well. Don't stay in one place too long. You want to heat the adhesive till it's goopy and work fast to remove the digitizer.
When the adhesive is slightly melted, gently pry up between the digitizer screen and the front cover. Try your best to remove the screen in one piece without warping or scratching the LCD underneath.
You can see where I damaged my LCD in the process.
After the digitizer is removed, clean up all the old adhesive as best as you can with a plastic scraper.
Step 5: (optional) Replace LCD
The LCD is held in place by two strips of adhesive on either side of the screen. Push from behind and slightly pry from the front, and the whole thing comes right off with the ribbon cable.
The new one sits right in. Be sure to thread the ribbon cable back through the right slot.
Remove the protective film before installing the new digitizer (next step).
Step 6: Install New Digitizer
Place double sided adhesive on the digitizer mounting points. The supplied kit only provided adhesive for the top and bottom of the digitizer which was enough to hold it in place. Use your own discretion. Don't forget to expose the front sticky side of the tape once it's in place on the phone.
Remove the protective film from the BACK of the digitizer, carefully slip the digitizer chip through the center hole, (may take a small push) and press the digitizer in place. It should fit snugly.
Step 7: Reinstall Internals
The rest of the installation is reverse of diassembly.
Take a second to clean out all the lint and dust that's collected on the circuit board. Gently brush them away or use some light compressed air. I had a dog hair stuck in between some of the chips. Thanks, Linus.
Carefully reconnect all the ribbon cables and small plug. The new digitizer chip has an adhesive backing you'll want to remove to secure the chip in place.
Press the back housing into place, reinstall the 7 small screws, put the data cards and battery back in, and snap the back cover in place.
Step 8: Revel in Your Like-new Phone
If you're good, your phone will look like the one on the right after you hit the power button. If your'e like me and have damaged the LCD under the digitizer, you'll have to replace the LCD as well (earlier step). Not to worry, you're a pro now and the second time through is much faster :)
So, enjoy your phone and try not to drop it again... but if you do, you know how to fix it!