You Control: Tunes, Control iTunes From The Menu Bar
I've slowly been trying to rate a bunch of my mp3's in iTunes. Its a real pain to be constantly switching to iTunes when each new song begins to rate it. I knew there had to be a better way. Google to the rescue. I initially found Synergy, but it wasn't free so I kept looking. My next search yeilded You Control: Tunes, which to my delight was free and fit the bill!
You Control: Tunes has a wide variety of features. Using You Control: Tunes you can navigate through your music via small back, forward, play, and pause buttons located in your menu bar (previously I used Bytecontroller for this). You can also rate the song that is currently playing by clicking on the star ratings next to the navigation buttons. Another neat aspect of this little application is that when a new track begins a small window pops up showing you the artist, song name, album art and other configurable information.
This helpful application has allowed me to easily rate my music while keeping most of my concentration focused at the task at hand. I'd recommend that you at least give You Control: Tunes a shot. Since its free, there's no loss if you don't like it. But, I doubt you'll be uninstalling this puppy!