Windows Mobile Users... Check this out
Song Recognition Cab (Update 10/28) - Page 4 - PPCGeeks
If you register (free) for the site you can get a download of this song recognition software.
It looks like it is made by Cingular, but it works on my Verizon WM phone.
I just tried about a dozen songs and it nailed the ID each time.
Pretty cool... and its free.