Ever since the lovely people at Google have started packaging the flash player into Chrome it's become a little harder to get the debugger version of the player working in this browser. Chrome will default to it's version of the player even after you've installed the debugging version. Here's the simple step you have to take, in Chrome go to:
Find the flash player, it should have 2 files as part of it, one is the built-in and the other is the debugger (you may have to click "Details" in the top right to see them). If you haven't installed it yet obviously you just see the built-in, and it doesn't matter the order in which you do install it. The trick is just to disable the built-in player, once you've done that chrome will use the debugger version you've installed.
To distinguish the 2 players the built-in will be located in the Google Chrome directory, default on OSX with Chrome v6.0.472.36 is:
/Applications/Google Chrome.app/Contents/Versions/6.0.472.36/Google Chrome Framework.framework/Internet Plug-Ins/Flash Player Plugin for Chrome.plugin
The debugger player will be located somewhere like (again on OSX):
/Library/Internet Plug-Ins/Flash Player.plugin