From what I've read online, the Canon rebel XS (Canon 1000D) isn't capable of multiple exposures with any special camera settings. That camera can only shoot at 3 frames per second (1.5 frames per second in RAW format).
There are a few ways to do multiple exposures, though.
You could set the camera for a long exposure (slow shutter speed) with a small aperture and use an off camera flash as a strobe.
The easiest way is to use a tripod or stay really still, shoot in burst mode at 3 frames per second and then assemble the image in Photoshop. It usually takes me about an hour to do one. This might help you, I can't find too many resources online that explain it well: http://photo.stackexchange.com/quest...r-action-shots
That's what I did with the below images, using a little Nikon D40:
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