The IM stuff really hurts my battery life as well, that could be because it means I'm always chatting away though . On average my battery lasts about a day and a half, which isn't great, but I can't complain too much.
same problems with battery draining fast, i actually turned of my phone after charging it and next morning (left unpluged but turned of) it beeped at me at around 6am and would not turn on, after plugging it back in to mains i had a battery symbol with lightning sign through it
I've tried all the above and one more thing that I think really helped. I can't fire mine up right now because I just put a full body protector on it and need to leave the battery out for 12 hours, but anyway I went into network connections and changed it from global to 1xev of something like that. I don't know if that shuts off the global radio or what? It sure seemed to help.