A flight instructor gave us a nice tip yesterday during the theory class:
Some big airports, like Chicago O'Hare or Boston, are streaming their radio frequency (ground, tower, approach/departure) on the net.
A good link is LiveATC.net
Enjoy! But solid knowledges in ATC and aviation are necessary. This is a very good site for "aviation enthusiasts, student pilots, student air traffic controllers, flight simulation enthusiasts, FBO operators, airline operators, and anyone with an interest in aviation communications. "
That said, for me, poor French, it's very difficult to understand... I'm curious to see what will happen when I'll have to land in Stuttgart (EDDS) !