I've been a big fan of all the battery saving measures and apps for the n900 . . . but for my own situation it would really be convenient to be able to have the wifi turned on for long periods of time and the phone network connected for internet usage & skype calls. however, so far I realize how this really drains the battery. still--any other ideas how to do this w/ some extra battery saving techniques that i may not have heard of yet?

Why would you need both Wifi & 3G on at the same time?