there are many battery optimization threads you might want to check out (with tweaks ranging from changing swap with swappolube, adjusting overclock and voltage, using autodisconnect, etc) but don't expect miracles - while my device can just sit around on wifi for 2 days checking email and updating widgets (only about 6 to 8 hours of the same on 3g), I get maybe 4 hours active web surfing max, less if things like bluetooth and gps are enabled, and about 30 minutes of skype video calling, which is the fastest battery drainer ive come across.