AssetTracker
AssetTracker is an add-on module for RequestTracker that helps with inventory tracking. Assets can be associated with RT users and RT tickets.
It is hosted on code.google.com, the project page is http://code.google.com/p/asset-tracker-4rt/
As of 2010-11-29: you have to get the 1.2.4b1 branch from SVN to get something that can be made to work with RT 3.8.x