Il Mio Problema
My battery of my 3G was not dying, it was pretty much dead already. As soon as I hit the web (with a fully charged battery) the phone shut down. Calls were only possible for 10 minutes, then the batterie died again
La Mia Riparazione
Following the step by step guide on iFixit, it was a piece of cake.
The steps were perfectly described and the pictures showed exactly what to do next.
I only learned not to use too much force when trying to remove the screen. I finished step 2 and three with one pull...
Luckily the cables came of smoothly.
Removing the battery was the biggest challenge. It was clued so tightly to the cover that I almost broke the spudger. Next time I go with the professional version...
Reassembling it was quite easy. In about 30 minutes I had a new battery and finally the phone is usable again.
Il Mio Consiglio
Add the separate spudger to the shopping cart, its worth the extra buck.
I will now repair all my devices myself before I go and burn my money on apple repair service :-)