If you're a serial updater and like to keep your software current then run, don't walk to check out AppFresh. I originally mentioned AppFresh on PowerPage Podcast Episode 64 and its become an essential part of my software arsenal.Think of AppFresh as Software Update for third-party software. It's essentially a free alternative to paid services (with an annual subscription) like VersionTracker Pro or MacUpdate Desktop.
When you run it, it scans your hard drive for applications, widgets, preference panes and plugins (InputManagers, Mail, Addressbook and iPhoto plugins as well as some kernel extensions) and compares them with the excellent online versions database at osx.iusethis.com for new versions and lets you download and install available updates easily.
AppFresh is built on update checkers like Apple Software Update (AppFresh integrates native update checking for Apple software), Sparkle, Microsoft AutoUpdate, Adobe Updater and osx.iusethis.com. It allows you to download many updates and automatically install them if you want. It also helps locating downloads and sends Growl notifications when the jobs is done.
Be careful though. AppFresh (currently 0.7.1) is a development preview, so there may be bugs. Also, always wait before installing any update to your production software. It's better to wait a couple of weeks and read up on critical software updates before installing something that's going to stop you from earning a living.