While browsing your iTunes library, you can start typing the name of an album, and iTunes will scroll along to the album in question. It seems to have a buffer, as typing The best of Paul Brady jumped past the other The Best of... albums I had to the reach the Paul Brady collection.
This is presuming that you have the music sorted by album. If it is sorted by artist, typing the artist's name will scroll to the first album by that artist.
You don't need to click in the search bar to quickly get to where you want. You can navigate iTunes entirely by keyboard which was news to me.
[robg adds: This works in any of the three iTunes view modes; just make sure that you have the listing panel active, or else your typing will choose items in the Source column instead. It's also not restricted to album and artist; whatever column you have elected to sort on will receive the characters you type -- song, genre, whatever...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20061012152419103