gdgt

There should be a setting in wireless setting/>Mobile networks then click Use only 2G. This is how it is on my G1 so Motoblur might have changed some thing but that should point you in the general direction.

And yes 3G uses more battery then Wifi which uses more then 2G so turning off 3G when not using it will save lots of battery.

Alright also to give u a heads up if u got the ota update u could always go into Settings > Battery Manager and set it up for either Balanced or Battery Saver mode.

Another option is to install an app such as TasKiller which once you train it to ignore the apps that you would like to remain running (Make sure that you put the VoiceMail app in the ignore list otherwise it will close your data connection every time the app is turned off) if once you are in the app you press the menu button and go into settings you can turn "AutoKill" to on and when your screen turns off it will automatically kill any running apps that are not on your ignore list, this feature is especially useful since by default Android keeps I believe 10 apps running at a time.

Welcome to the CLIQ family and enjoy.