There are lots of good places on the internet for photography tutorials and techniques. If you spend some time with the camera, I think you'll like the increased control you have over the pictures vs. a point-and-shoot. It drives me crazy to shoot with a P&S now that I've gotten used to using my XTi. Here are a few links that I think are good:
Canon Digital Learning Center
Cambridge in Colour - great site for very in-depth technical info on cameras and photography in general, and also an incredible gallery of night shots
Luminous Landscape Tutorials
Ritz/Wolf Camera Tutorials
Photoworkshop.com - a lot of different info on here...go to the "Photo 101" link on the left and scroll to the bottom for free downloads of photography books...also click on "Learning Centers" for links to other resources on the net.
I will say this though - if you want to be able to get the most out of an SLR, you'll probably need to buy a decent amount of accessories. A couple decent lenses, an external flash, and a tripod are great things to have, although it's possible to take good pictures handheld and make up the shortcomings of a lens in post processing. The kit lens (not sure which one came with your camera) leaves quite a bit to be desired, but can take decent pictures if you stop it down to at least f/5.6. My advice - go buy a Canon 50mm f/1.8 II for about $85. A fixed focal length lens (meaning it can't zoom, called a "prime" lens) is a great learning tool when you're starting out. It forces you to think about composition, and it's fast enough (meaning it has a big aperture) to let you learn about the relationships between aperture, shutter speed, & sensor sensitivity (ISO), and how you have to modify them as ambient lighting changes.
Good luck and happy shooting! :sombrero:
EDIT: one thing I forgot to mention - don't forget that it's really simple to "ease" your way into digital SLR shooting, especially with a camera like the XTi. The camera's Auto mode (A on the dial) is basically just like shooting with a P&S, except that you have to look through the viewfinder and rotate the lens to zoom. Once you get comfortable with that, start using the Program mode (P on the dial), which will let you control a little more of the picture-taking process. After you're comfortable with that, start using Aperture Priority (Av) and Shutter Priority (Tv), although you'll probably use Av the majority of the time. You'll be surprised how quickly you can become skilled at using the Av and Tv modes.
EDIT #2: I finally found the tutorials I had gone through when I first got my camera, and they helped me quite a bit. Here they are:
http://www.usa.canon.com/content/rebelxt_tutorial/rebelxtlessons.htm
