Readers send me links to the very coolest mapping sites. I've collected a batch. Most are educational (admit it, since high school, your skills in geography have dropped lower than the lower 48); others are hooked into Google in a variety of ways.
I found the Third Grade Geography Test on the Internet almost five years ago. It's been amazingly popular. Since I popped it on my site, there have been over 600,000 hits. Don't let the third grade thing fool you. It's tough even for grownups. You get a short amount of time to drag and drop the name of a state on its location.

Get a handle on the States with the
Third Grade Geography Test
You may be interested in the States Web Game, a more sophisticated mapping program, appropriate for mid- and high-level classes. It's like a jigsaw puzzle -- you get a blank map of the United States and as the program offers you states, you have to stick them in the right spot. I did pretty well with Florida, Texas, and California, but those tiny eastern states are a killer.
I haven't forgotten about those of you in Europe. Try out the European Countries map -- a tough one, for me, at least.
The Animated Atlas Growth of a Nation is a great learning tool showing the history of the United State's development from 1790 through 2000.
You can find even more mapping programs, with lots of levels, at Sheppard Software.
Click here for more mapping sites.