iPhone4 died, Apple Store wouldn't touch it b/c it's enrolled in the dev program
5 - 30 minutos
Needed the phone to last until the iPhone 5 comes out.
Battery was hard to remove, but the video assured me that as long as I didn't use the tab I would be OK. Sure enough, they used a lot of glue/tape to hold it in - but the plastic tool got it out. After replacing the battery, and charging it for hours, nothing happened. I tried entering recovery mode, nothing. In the end I just left it plugged into my PC with iTunes running and forgot about it. About 6 hours later, the phone turned on by itself. Go figure.
Don't be afraid to try the simple repairs yourself - it's really easy. Go for the Pro Tech Toolkit, it has tons of useful tools you will use for years to come.