Kensington, maker of a full line of mice and trackballs, has released an OS X version of their popular MouseWorks software. The MouseWorks software allows users to custom configure buttons on their Kensington input products, allows users to get the most functionality and productivity from any of Kensingtonis products. According to Kensington:

Attention Kensington MouseWorks BETA testers. MouseWorks for Mac OS X version 1.0b1 is now available and can be downloaded from http://www.kensington.com/support/sup_1357.html

About This Release This is a pre-release version of MouseWorks for OS X. Kensington is making this beta release publicly available in order to get as much feedback as possible regarding bugs and compatibility issues. We will work hard to identify and fix all major bugs before the final release of version 1.0. However, because this is not a final release, it has some rough edges and has not yet undergone the level of internal testing we feel is adequate to ensure a problem-free experience. Therefore, we recommend that you treat this release as you would any other beta software. Be sure to back up any important files before installing this software. Do not use this release on a "mission critical" machine, because we cannot guarantee freedom from errors, crashes, or other anomalous behavior.

You can find more information about the full line of Kensington products at their Web site.