A while back I was creating a couple of mix CDs in iTunes for Windows and I wanted to print out a booklet with the lyrics for each song in it.
Once I got all the lyrics for the songs entered into iTunes, I realized that while you can print CD covers and track listings, there's no option for printing the lyrics. So one evening I whipped up a (very) crude application to do that.
The app is designed around printing CD booklets - it does its best to lay the lyrics out to match the size and shape of the covers which iTunes prints. It prints on the front and back of each page, arranged so that you can cut out the pages, fold them in half, and everything reads in order like a booklet. It does the best it can to lay out the lyrics you enter so that they fit on the pages in a readable font size. Use at your own risk, YMMV, etc.
If nothing else, this should be a decent starting point for someone looking to print out lyrics in other formats (or just extract lyrics from iTunes for other purposes). It uses the iTunes COM interop library that's installed in Windows when you install iTunes.