www.dpreview.com is the digital camera bible.
that being said, I just bought a Canon SD700IS, and Canon announced the 800 and 900 2 weeks later

. I can laugh about it now, but it hurt last week.
Here's another thread on the subject:
http://www.xoutpost.com/lounge/19883-...highlight=kata
you can't go wrong with the SD550, 700, 800 or 900. The differences are MP and Image Stabilization. Take a look at the reviews on dpreview.com, it will be a big help.