I'm looking to create a new tab in the Task workitem template, called Hours. It will allow a developer to log hours it takes to complete a task. I would like it to be in a separate tab becuase I want it to be able to add multiple logged hours for a particular task, so I'd display it in a DataGridView. My question is, I don't believe the TFS databse is setup for this 1 to Many relationship. Does this mean I would have to create my own tables and data access functions? Or can TFS tables be extended for this purpose? Thanks.

More than likely you would have to create a custom control to do this.

You may or may not have to create your own tables/data access, depending on how you create the custom control, and want to store the data.