Digital SLRs can take more diverse pictures
Compact cameras are designed for maximum portability so they are made to be small and light. In the case of digital SLRs, the priority is on shooting. To make it fast, easy, and flexible to shoot a wide variety of subjects. The digital SLR can use various lenses to take wide-angle, telephoto, or close-up shots. And through the viewfinder, you can see what the lens sees and the exact scene that will be recorded.
VERY GOOD tutorial for Digital SLR cameras by Canon
http://web.canon.jp/imaging/enjoydslr/part1/1B.html
http://web.canon.jp/imaging/enjoydslr/part2/2A.html
http://web.canon.jp/imaging/enjoydslr/part3/3A.html
http://web.canon.jp/imaging/enjoydslr/part4/4A.html
Important Terminolgy
http://web.canon.jp/imaging/enjoydslr/terminology/index.html