[Chris.]

You have the rebel XT or XTi? There is a dedicated button for WB at the bottom of the directions buttons next to the screen on the XT and XTi. It looks like it's a round button just above the directional buttons on the XSi...

Your goal is to get the picture to look how you see it and the whites to be true white. If you are using fluorescent light, set it to the long bulb, etc...

EDIT: Something just hit me. What mode are you shooting in? Please don't tell me auto. lol! I can't remember if you can make adjustments to wb and ISO and all that in auto on a dslr. I haven't had one in about a year. You should really try your hand at shooting in manual mode. It's the only way to take full advantage of having a nice DSLR IMO. It just takes practice learning what settings to use for shutter speed, ISO, Aperature, WB, AF, and all the other cool settings.