Removal is pretty difficult - I haven't worked on 360's for a while, but I do remember failing at taking a fet off.
The Iron i used was probably 20 watts? I'd wager a 40 watt iron is hot enough to do it (that's what I use on other consoles i work on)
As far as the actual removal goes, the fet has 3 contacts - do them however you want, but make sure you DON'T attempt to pry it off of the motherboard.
The area marked in red will be the most difficult. It acts as a "heatsink" - you'll need to be patient with it >.<
refer to THIS
if you have further questions.
**I haven't done it personally, but it's possible to test without removing the fet entirely too. I assume you'd desolder/cut the legs of the dead one, then solder the new fet in (not attaching the heatsink pad) - Anyway, best of luck with this! Hopefully you're not wasting a lot of time/effort on a dead box This post has been edited by gummyworm31: Feb 10 2012, 06:42 AM