Yeah I have the same one, and was extremely happy when I found it. I just let my iTunes run on mute when I am away from my computer and leave my dashboard up. It took a few days, but I'm happy I did it.
I wish there was a decent one for windows users. Can anyone suggest one. I was doing it the hard way last night. Cut and past to info page.... that will get old fast even with the small library I have,.
There is a paid app with a free trial called Songgenie.
Plus you can search the thread Your Geektool scripts for geeklets that pull lyrics from the Internet. Success is varied on this one though. I use a Geeklet and it doesn't always work.