Sensor Cleaning?

I'm terribly sorry if this is a super newbie question, but alas, I've only had my camera for about a year, (Digital Rebel XT, 8mp). When should I start thinking about cleaning the sensor? And is it a good idea to get it professionally done, especially if I'm unsure of what I'm doing? ... I saved for an entire summer to buy my camera, I would rather poke myself in the eye with a rusty nail than hurt my baby...

I would clean it when you notice dust spots in your pictures. Of course the best thing is preventing it from becoming a problem in the first place. I try to clean mine after every outing. Get yourself a giottos rocket blower, put the camera in cleaning mode (look it up in your manual), and give the sensor a few good blasts with the blower (but dont touch the sensor with it!) while holding the camera so the opening is facing downwards (so dust falls out rather than back into the camera).

This method should take care of most dust problems. For really stubborn stuff you can get sensor cleaning swabs and solutions. I've never had to use anything besides the blower though.