On the new Apple keyboards, you not only can use the keyboard to make iTunes pause, or jump to the next/previous iTunes track, you can also seek forwards and backwards: by holding down F7 (Previous) or F9 (Next), iTunes will seek backward or forward.
[robg adds: This mimics the behavior of those buttons in the iTunes interface.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071105072152726