NFVersionChecker for Mac

From Forgotten Newbies:

A free Cocoa class that lets developers set up version checking with zero effort. It notifies users of the developers program when a new version is available and has a direct download button. (that can point to VersionTracker!) Also included are:

• Support for automatic version checking - suppresses error messages and notification that the program is up to date, it will also suppress new version notification if the user has chosen to skip this version
• Support for manual version checking - always shows new version window if there is a new version, or an error, or current version
• Statistic generation - your web logs will tell you what version has checked for a new version, and weather it was automatic or manual
• Easy to use - just add 2 lines of code!