Single Server Deployment
If you want to run SharePoint 2010 on the same box as TFS 2010 then make sure you install it before you install TFS 2010. You will then have to use the custom configuration wizard so you can use the existing SharePoint instance.
Multi-Server Deployment
If you are going to have SharePoint 2010 on a separate server to your TFS 2010 then you will need to again run the Custom configuration wizard, but you will also need to Integrate your SharePoint 2010 instance with TFS 2010.