You want details? How about lectures from the people making the services on the latest version of BPOS hitting the web this weekend! I'm super excited to annoucne tha availability of the Virtual Airlift webcasts on the Technical tab of this site.  New features for Exchange, the administration console and other parts of the service are all detailed by the PMs at Microsoft in charge of those features.
You want to know about how secure our data centers are? Check out Mike Ziocks highly rated presentation
Interested in SharePoint Online capabilites? See it for yourself
How about Exchange Online and the new Conference Room features? See Ed Wu in his psychedlic shirt at
Of course, there's using the Administration Center including how to add a custom domain to BPOS:
David Wang presents a demo and details about the single sign on tool. Important details are included about how to deploy and configure.
Check out all the Virtual Airlift content on the Technical Tab!
Also, note there's new Business content too on the Business tab.