I made a quick PHP script to let you practice calculating pot odds and knowing the odds you're getting with some number of outs with one card to come. It's not all flashy and whatnot, but I figured if I was only going to spend 10 minutes of my time then it shouldn't have to be.

http://www.ssgrinder.com/pot_odds_trainer.php

Any feedback is welcome, although I doubt I'll change anything.