One of the best sites you can review for learning the camera is www.photonhead.com. Check it out.
Keep in mind the Aspect Ratio of your VIEWFINDER vs. an 8x10
Not all digital cameras are created equal. Small point and shoot cameras have small sensors, like the one on the right (not labeled) versus the full size digital SLR (middle) which still has a sensor smaller than the size of a 35mm negative. The sensor on the far left is for a very expesnive DSLR with a full size sensor.