I put a new one in my sister's iMacDV 400 a couple years ago.
If you have a steady hand and patience you can do it. But you will have to take several parts off the bottom of the machine to get at the battery. It is in a location that is not that easy to reach if you have big hands. Also I suggest you either get one of those screwdrivers that has the little clamp on the end to hold the screw. I couldn't find mine so I stuck the end of the screws into a glue stick which gave them enough stickiness to adhere to the screwdriver while I threaded them back into their holes.
Kind of depends on how valuable your time is and whether you have $30 extra. On the other hand, it will also take time to bring the Mac to the repair place and wait for them to do it...
A few minutes later:
This rang a bell and I did a search:
Déjà vu all over again..
http://www.techsurvivors.net/forums/index....;f=1&t=7724http://www.techsurvivors.net/forums/index....;f=6&t=7281Oh dear, what's happened to my memory? I must need at least twenty more gigs of RAM upstairs. It's scary, seriously. My jaw dropped when I read myself asking the same question last year. Will I ever quit trying to save everyone's old macs?