IBM have a Beta Card-Sorting tool that helps interface designers organize information based on users’ expectations.
The software comes with 2 packages – USort and EZCalc, and can be used as virtual cards and can generate card lists and tree diagrams. The 2 packages are used in designing Web sites, program interfaces, and other information design applications.
There are other similar card sorting tools available, including:
1. Classified
2. WebSort web-based (PHP)
3. CardZort
Louis Rosenfeld (co-author of the O’Reilly IA polar bear book) has referenced Andy Edmonds, a human factors masters student’s online card sort tool – uzCardSort. His tool website also contains a great list of other available card sorting tools.