If you're on a 15" or 17" PB, you'll need to hold down the fcn key (function) to get to F9-F11 because the keyboard brightness functions get priority on those keys. F9 F10 and F11 are the keys for Expose, a feature wildly more useful than "minimize all windows." If you like the functions (tile all windows, tile app windows, move all windows and show desktop) then you can set up hot corners in the Expose panel of System Preferences.
For example, when i want to move all the windows out of the way to get to my desktop, the bottom-right of my screen is the hot corner for that function, so I just throw my mouse down and right to accomplish this. Upper right is the show all windows Expose function, so I just mouse up and to the right. Bottom left is show all app windows on my machine, which is useful for having tons of chat windows open but with some buried behind other apps.
And I strongly suggest using iChat instead of AIM. iChat *is* AIM, but without the horrible interface, advertisements, and constant crashing.
-Drew