This is really picking at nits but for the benefit of future, perhaps less experienced and/or less informed, readers of this thread it should be noted that on Apple's current laptops and keyboards the user must also press and hold the fn key at the bottom far left of the keyboard to activate the F1 through F12 functionality. On these keyboards pressing F9 alone skips to the next tune in iTunes and F10 alone mutes the standard audio. So on these keyboards, to "Exposé" all windows for all applications press fn+F9 and to "Exposé" only the current application's windows press fn+F10.
This is made even more confusing because System Preferences > Exposé & Spaces > Exposé only mentions F9 and F10, ignoring the necessity of using the fn key to activate the F1 through F12 functionality. Note too that on third party and some older Apple keyboards this is probably reversed. In other words fn+F9 would skip to the next iTune while F9 alone would Exposé all application windows. I have fixed supposedly broken keyboards by pointing this out to the user.
