Agendus is a replacement product for the Palm and can be purchased with a desktop program for your computer. It can work with the Palm Desktop or Outlook. It is basically a shell that uses your Outlook data but gives you some interesting features:
1. Being able to color projects, tasks, etc.
2. Being able to attach icons to projets, tasks, etc. I use this to subdivide my projects into tasks. By giving each task the same icon as the project, I can immediately pull up the project and all related tasks and filter out everything else while I work on the project.
3. If you are a Palm user, it allows you to use the to do list, calendar and contact list without switching programs.
4. Allows you to attach contacts to appointments and tasks for tracking purposes.
You can find it at http://www.iambic.com