SongGenie, on the other hand, has no social life--since it's just an application after all--so all it wants to do is figure out which songs you have in your iTunes library. The first time you launch SongGenie, it starts crunching through your iTunes library, identifying songs that are either missing information or where the information included in the track doesn't look right (for example, the name starts with a number) and collects all those tracks in a 'Songs with missing information' list.
You can then go through this list and either have SongGenie identify each song individually or select a large group to have them mass identified. SongGenie uses each track's "acoustic fingerprint" to gather its information, but you can play the track in iTunes before you apply the suggested changes, just in case SongGenie is wrong (the person I spoke with from equinux said that SongGenie has a success rate of about 90%, though, which isn't too shabby).
SongGenie costs US$29.95 and requires Leopard (OS X 10.5).