I've been watching the Amazon prices for a while. This has been stuck at $630. I own an original Digital Rebel, so I have a collection of lenses and was only interested in upgrading the camera body. For a week the price dropped to $575. It has bounced around since then (see below). So be patient and watch for a while to get the best price. The current $568.95 is the best I've seen ever on Amaz0n.

There have been a lot of similar or slightly better deals (particularly at D3LL), so do a search to find the best deal for you.

Deal Details:
Canon Digital Rebel XSi
12.2 Megapixels, 3" LCD screen
Body Only
was $574.98 (silver is $630) from Sep 30-Oct 7
was $584.98 (silver is $621) on Oct 8
was $579.00 (silver is $600.88) on Oct 12
was $568.95 (silver is the same) on Nov 12
was $567.95 (silver is $649.05) on Nov 20
Silver now $563.97 (black is $567.95) on Nov 29
No lens included!

This is direct from Amaz0n, so subject to free shipping, Amaz0n Prime, and 6 points per dollar on your newly updated Amaz0n/Chase Visa!

Optional Addition:

25% off Vista Explorer 60" Lightweight Tripod, regularly $36.
See details on camera order page.

Linky

This is the cheapest by far I've seen on the Silver body. I prefer the black and bought it back at the original posting date, but if people are looking for the silver one, and already own some EOS lenses, this is the way to go.