To quickly rate songs in your collection, download PTHiTunesNotifier from PTH Consulting.
http://www.pth.com/PTHiTunesNotifier/
Setup the hotkeys function so that you can use your keyboard’s function keys to rate songs as they play. If you work on your mac all day you can rate your collection in no time!
Not only do you gain the ability to quickly rate your songs, you get a great on-screen display of each song as they play!
If you setup the Start/Stop, Next, & Previous Track hotkeys, you will not even need to switch to iTunes to change tracks anymore!
You might also want to check out Synergy which adds the ability to display album artwork!