I've just found a cool little Applescript for iTunes, that'll make it possible for you to find lyrics for songs in the iTunes library,- from within iTunes. If you click the image above you'll be taken to a page called "Jon's little page of Applescripts". Jon has created a script called "Search for Lyrics",- download the script (left side of the page: "Search for Lyrics"), unstuff it and place the script in: Harddisk->Library->iTunes->Scripts. If you don't have a folder called iTunes in the Library-folder, with a folder in it called Scripts, you'll have to create 'em first.
Launch iTunes and select a song, go to the script-menu (located between the "Window"- and "Help"-menus), and select "Search for Lyrics". You default browser will now launch and take you to AstraWeb's Lyrics Search Engine and show you a link to the lyrics (just click "Accept" etc. and eventually "Quit" when the pop-up appears). Great isn't it :-)...and it's FREE!