Official Writeups at the following URLs:
Microsoft Forefront Products
If you are not a MSAV customer contact your AV vendor and work with them to get samples and definitions!
Action Plan
1. Set a Transport Rule to Delete any incoming messages
2. Delete messages in the queues
1. Export and delete virus messages from mailboxes
2. Preventative Measure - Disable MAPI access
2. Clearing queues
Changes in the Outlook 2007 Security model that allow programmatic email sending when the Security Center reports AV status that is up to date / running http://msdn.microsoft.com/en-us/library/bb226709(office.12).aspx