Best non-IM use of iPhone 3.0′s push notifications yet: Prowl is a $3 app that pushes Growl notifications from your Mac to your phone.

Growl’s a global notifier that plugs into everything from BitTorrent apps to iTunes to Mail.

The possibilities really are endless: You can be pinged with a push notification when a torrent finishes downloading, you get a new IM or email, you’re mentioned on Twitter, or anything else Growl can notify you about.

While Prowl’s designed for push notifications from a computer running Growl—opening up a world of possibilities: GVMax and Prey Fetcher push Google Voice SMS and Twitter messages via the web, without your computer running Growl 24/7.

The downside is that you’re trusting your Google Voice and Twitter logins to third-party services, but if you wanna get push notifications about @mentions or DMs from Twitter or SMS messages from Google Voice without keeping a computer running at home with Growl whenever you’re out, they’re the way to go.

Any other services that use Prowl this way?