LyricSnapper for Windows — auto-tag your mp3′s with lyrics as you play!
One of the coolest little functions I’ve found on my new iTouch is the lyrics support for mp3′s. I’m new to the whole Apple thing, so this little feature really excites me. I can’t speak for any other formats besides mp3 because I don’t use them, but this freeware is still worth a shot if you want easy lyrics encoding.
All you do is install LyricSnapper and then set it to sync with iTunes. Now whenever you play a song in ye olde grey media player this handy little app will search lyrics sites for the lyrics. The program can auto-save a song’s lyrics to the id3 tag even if it’s only played for a moment, and so I’ve just been through my entire bloody library of songs. I play a song for half a second, make sure the lyrics are correct (you can choose several websites to check — giving you lots of different choices), and then move on to the next tune.
I’ve finished tagging around half of my library (it’s exhausting), but it’s awesome to see the lyrics for songs pop up with just a tap on my iTouch’s album art.
Just thought I’d share the news, in case more of you out there want to torture yourselves by pressing "next" on iTunes for about four hours straight so you can tag everything 
Wow, nice find! It’ll take a lot longer than 4 hours I think, but at least I can get it done for the stuff I play most often.
Thanks, and, most of all, good luck!!! Darn these large music libraries