What should I use for syncing TFS 2008 Work Items with an external database?

What should I use for syncing TFS 2008 Work Items with an external database? I just want basic functionality such as creating and updating work items in TFS so that they match our QA department's bug tracking software.

You can consider to use the Integration platform of TFS: http://tfsintegration.codeplex.com/

If you need to do it in an automated fashion, it is straightforward to do it with the API. Just modify your work item template to have an external reference for the bug-tracking system's key. That way you can keep things straight.