There are a bunch of similar questions on SO:
- automate-interaction-with-a-gui-interface (Edit: no longer available)
- automated-testing-of-windows-forms (Edit: no longer available)
- automated-testing-of-gui
In my experience, there are a lot of good open source tools for the web, but not so much selection for open source thick client test automation tools. If you want good support with robust functionality, especially recording, you will need to look at the commercial tools (QTP, RFT, TestPartner, etc...)
