Ally (iMuggle) is killing it with her new weekly column on mods and DYI repairs. Check it out, and post any questions you have, or ideas you'd like for future columns, right here in this forum!
http://www.tipb.com/2011/12/06/tipb-weekly-mod-replace-battery-iphone-4/
http://www.tipb.com/2011/12/06/tipb-weekly-mod-replace-battery-iphone-4/