One neat little thing about the iPod and iPhone family of devices is their ability to display lyrics -- supported by all iPod nanos as well as the iPhone/iPod touch, and iPod Classic 5th generation and higher. On the iPhone and iPod touch, lyrics show up when a song is loaded (and can be re-displayed by tapping on the screen while a song is playing); while on the iPod nano, pressing the center button several times while a song is playing will cycle you through to display lyrics.
Among other things (like fetching album art and last.fm scrobbling), GimmeSomeTune can fetch and tag lyrics to the current song that's playing. No need to worry if the songs already have lyrics -- GimmeSomeTunes will leave them alone. To enable lyric fetching support, click on the "Artwork, Lyrics" pane within the app's preferences and place a check mark next to "Fetch lyrics from Internet, when song has none."
Okay, now what if you have a large iTunes library? Surely, clicking and playing each song in it would take several light years. This is where Needle Drop comes in handy. The Applescript plugin, supplied by the resourceful Doug Adams of Doug's Apple Script's for iTunes, plays a track for a specified number of seconds before proceeding to the next one. While Needle Drop provides a great way to quickly sample an album, for our purposes we'll be using it to do some rapid drive-by-playing of our iTunes library. I find that a 5- to 10-second buffer usually does the trick.
Why do you even need a 5- to 10-second buffer? Why can't you play tracks in shorter intervals? Well, too short of an interval could result in the following problems. First, it may not be enough time for GimmeSomeTune to tag your music. Second, and more importantly, shorter intervals may result in a slap on the hand from Google, who may give you a not-so-pleasant warning; such warnings were also commonplace with PearLyrics in the middle of processing large libraries.
Obviously, this process will take some time. My advice is to mute your iTunes and let it run overnight (or two, depending on how big your library is). So kids, don't try this at home. Try this at grandma's house. You know she'll let you get away with anything.
If you have a different or better way to batch fetch lyrics for your iTunes library, let us know.