Launch it, then play the song in iTunes. The lyrics are downloaded and pasted for you in the Lyrics section of the song's iTunes entry so fast that you’ll literally miss it if you blink. Double-click another song to start it, and its lyrics, too, are downloaded in a flash. In this way, you can fill in the lyrics of virtually all your songs collection in as many seconds.
I say "virtually", because iClip Lyrics gets the lyrics from a particular website – LyricWiki.org. So Parachutes by Jenn Grant stumped it, but all the songs in Alanis Morissette's Jagged Little Pill or Sting's Fields of Gold came up immediately. Of course, that's not iClip Lyrics' fault, which does its part even better than one could hope. You can download and use iClip Lyrics for free, but it's easily worth a donation of $10 or more. Enjoy.
(Source: Macworld) | Cost: Free (donations welcome) | Requires: Mac OS X 10.4+, iTunes 7+ | For further info... ^QQQQQ