http://www.dpreview.comGreaqt info on all of the above mentioned cameras, but better than that there are dedicated forums for each and you can get feedback from semi-professional and hobbyist users on these cameras and see a ton of photo samples. I purchased the Digital Rebel as a gift for my fiancee who is a hobbyist and she loves it.
in regards to te other questions with a drebel:
2.) you can use manual focus on the canon cameras no problem. Autofocus is pretty simple to use but not always perfect. you basically pus the shutter button down halfway and it focuses.
3.) at 6.3 MP the difference is pretty minimal, film is still better if you do the darkroom stuff yourself and are focusing on portions of the negative etc, but you can do a lot with digital manipulation that you can't do with straight film. Straight answer, film is better at print sizes bigger than 14x22 for 6.3MP but to that point they are pretty comparable.
4.) Not really.
5.) minimum 256MB (drebel stores about 70 images on a 256MB card). cameras with higher res than 6.3 will store fewer images.
One thing you absolutely must do is get a high speed card. this is not like high speed film. with a faster card you can shoot more images in a shorter timeframe. the camera must write about 4MB per image to the card and this takes a little time. In practice I can get about 8 shots in a row very rapidly (don't remember the exact images/second off the top of my head) before the camera needs to spend a second or two writing to the card (our card is 12x)
hope this helps...but seriously dpreview is the place to go.