STATESGAMESONLINE

Easy

http://www.sheppardsoftware.com/USA_Geography/USA_G0_click_1024.html

Medium

http://www.sheppardsoftware.com/USA_Geography/USA_G1_1024_768.html

http://www.sporcle.com/games/g/stateabbreviations

Hard!

http://www.sporcle.com/games/g/states

And...if you get tired of the US:

http://www.sporcle.com/games/g/japanprefectures

AND FOR YOUR CELL PHONE! Please download fromm apple store or google play.

http://digital-gene.com/app_usmappuzzle.php?lang=en