Yeah, the rebel's flash sucks hiney too. It kind of points down, so if you get a bigger lens, the lens gets in the way. But you can get external flashes (my birthday's comin' ).
Prin is correct! In general those teeny pop up flashes are terrible for creating fabulous phohography.
So yup...save money and get an external flash if you are into seriously bettering your photography. With one of the external flashes, you can bounce the light or take the flash off camera which is WAY more creative - also external flashes SERIOUSLY reduce the chance of getting red-eye.