Growl is a well known 3rd party alert system for Mac OS X and provides heads up display of incoming email, twitter, file transfer, chats, downloads, and just about anything you can shake an "I want to know" at. And Windows users, don't you fret -- they're working on a beta for Microsoft's platform as well.
Prowl takes Growl alerts and send them on to your iPhone (or iPod touch), and you can configure the type and priority level you want to get. Up to 30 days of notifications are logged, and links remain active in the alerts.
For hardcore status trackers, this might just be a dream come true. For those who think one more alert will send them over the cliffs of insanity... best stay well clear.
If you do try it out, Mac or Windows, let us know how it works for you.