Reply to Message

http://metaquark.de/appfresh/

It's in Beta right now, and will continue to be free during development. The developer is making noises about trying to keep the software free for personal use.

AppFresh checks for updates against the database maintained at iusethis.com. That's not as diverse as checking 3 sites, and AppFresh doesn't allow the declaration of custom update targets.

It can be set to download and install updates, if that's desirable.

VersionTracker also has a proprietary 3rd-party software update app, but they at least offer a free trial.