Your iOS device's headphones with remote controls also start/pause/ffwd/volume change your Mac.
Plugging your iOS headphones (with remote control) into your Mac, the headphone remote functions will change volume, pause, fastfwd, rewind and track skip iTunes.
Tested on MacBook Pro mid-2010 with OS X 10.7.2
[crarko adds: This is an update to an earlier hint. I see in the comments of the previous hint that there are some Mac laptop models this didn't work on.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20120129160111964