It took me about four hours from start to finish.
What you need:
sweater that has a double lining (head phones go in between the linings)
over ear head phones
needle and thread (you might want to read this great instuctable, www.instructables.com/id/How-to-Sew
saran wrap or a sandwich bag
8-10 safety pins
two normal sized rubber bands
Here is how I did it
First, take apart some over-ear head phones... I'm not going to walk you though this because it wont be the same for everybody but remember you need to leave some plastic around the front of the speakers.
Step 1: Waterproofing Headphones
Once you got the speakers out of the housing, use ether saran wrap or a sandwich bag and cover the speaker. Take the paper clip and wrap it around the plastic tightly, snip off any excess paper clip.
Tear off some excess or the bag or saran wrap so there is a few inches of the bag or saran wrap coming out from the other side of the paper clip.
Twist the loose bag or saran wrap tightly around the wire and then carefully light the bag or saran wrap with a lighter to melt the bag or saran wrap around the wire. BE CAERFUL! the melted the bag or saran wrap IS hot and if touched it can stick to you and BURN!!! Also, Don't hold the flame to long you do want to melt the headphone wire!
When it has cooled, take some electrical tape and starting on the headphone wires wrap the tape around the wire until you reach the base of the speaker.
Step 2: Adding Ear Cushions and Opening Up the Hood.
When you try to flip the hood inside out the safety pins will restrict you from flipping the hood fully inside out. You will need to put in anther safety pin just through the inside layer of fabric (for me it is the furry layer) and remove one safety pin the is passing throug both layers. Add and remove all for safety pins so they only pass through the inside fabric and though the headphone cushion so you can flip the hood inside out.
Step 3: Sewing Ear "cushions" and Speakers
Sew the lip that is on the headphone cushions on to the hoodie. Don't sew anything else but the lip or else the cushion will not fit around your ear.
After you sewed both cushions on, get the speakers and put one of them in the middle of the ear cushion on the inside of your hood. Then, sew across the speakers so that they wont move. Put the smallest amount of supper glue on some of the places where the thread cross each other.
Step 4: Finnishing UP!!!
I use a head band and cut it in two and tide a knot so it would blend in better.
Next Sew up your hoodie. I passed the wire over my seam instead of cutting a hole in my seam and risk something unraveling. I ran the cord in to my hoodie pocket where I keep my old shuffle. Now I can enjoy my tunes all though the fall, winter and spring!!!