EDIT: Please see Aaron Block's excellent guide to understanding TFS communiciation architecture along with tips to set this up. I have just added my thoughts in here on top now that i have found this doc:
Organisations may wish to expose their Team Foundation Server resources (including SharePoint Team Sites) using fully qualified domain names (FQDNs) both internally and externally. This document provides (almost) complete guidelines on how to do this, with particular focus on the TFS and SharePoint configuration to support FQDNs.
Install TFS 2010 Beta 2. This guide assumes a single server installation, but could easily be interpreted to work with multiple application tiers.
Set up your FQDN. For internal access, it's recommended that you update your DNS Server internally (e.g. Forward Lookup Zone for tfs.yourcompany.com) to ensure that the FQDN points to an internal IP Address when users are connected to the network (to avoid having to route out to the internet and back).
For external access, add an A record for the FQDN to the DNS zone file for your domain (via your ISP’s control panel normally). You will need to configure your perimeter network appropriately to route public 80 and 8080 (or 443 if you are going secure, not covered here) traffic through to your TFS server which is not covered here. (Although I intend to post separately on doing this with ISA 2006 soon).
Ensure your FQDN is working internally and externally as expected before continuing to configure TFS and SharePoint.
Disable the Loop Back Check on your TFS Server. http://support.microsoft.com/kb/926642. This is required otherwise the TFS Admin Console will throw errors as it won't be able to access your FQDN
Restart your server
Add your FQDN to the alternate access mapping of SharePoint for the TFS Web Application using SharePoint 3.0 Central Administration > Operations >Alternate access mappings (use 'Add Internal Urls').
Change the RS & WSS locations by directly editing tbl_LocationMapping table in the TFS Configuration database, adding your FQDN in. (Aaron has advised this is definitely not necessary, as these urls can be altered in the TFS Admin Console, see below)
Restart IIS 7.0
Open TFS Admin Console, select Application Tier, then click on Change URLS.
Put your FQDN in the Public Url field and change the Server Url to continue to use the netbios machine name and then click OK. and click OK
Select Application Tier > SharePoint Web Applications, then select the top row in the list within the SharePoint Web Applications list box. Click 'Change SharePoint Web Application' and put your FQDN in the Friendly Name and Web Application Url fields and click OK.
Select Application Tier > Reporting and click Edit. Ensure that your FQDN is used for the Warehouse Database, Analysis Services Database, Report Server Url and Report Manager url.
Start all services again once this is completed.
Within the TFS Admin Console, select Extensions for SharePoint Products, then select the top row in the list within the list box.
Click Modify Access, and ensure the FQDN is added to the URL for Team Foundation Server and click OK.
Note! Excel Reports on the SharePoint sites don't work unless you open ports for Analysis Services (link to follow...)
You should now be ready to go!
This post builds on the work done in the post below, but is updated for Beta 2 and also includes additional configuration.