the camera does have an AF Assist beam, its the little white thing beside the shutter button. it works all the time, not just when the flash strobe goes off. the flash strobe only goes off to help focus and verify ligthing under less than favorable lighting conditions. or.. when ever it likes.. canon is wierd like that.
i am not sure why, but canon thinks its ok to put it there, right where your damn hand is.. its stupid.