Steve Vai has a previously unreleased song on the album The Songs of NASCAR entitled Rush. You can preview and purchase the song using this link. If you are a hard core Vai fan who just has to own every recording he has done, go get it. Otherwise, since the song is only a little over a minute, your $0.99 would be much better spent on one or more of the following:
All of these can be also be found in the Essential Vai iMix on iTunes.
Links to songs require that you install iTunes.