• White paper: Groove Enterprise Services Security
• White paper: Groove and SharePoint Integration
• White paper: Groove Backup Options
• White paper: Groove Security Architecture
• White paper: Finding the Groove Relay Version
• White paper: Safeguarding Your Groove Relay Password
• White paper: How to Secure a Groove Server Manager Web Site
• White paper: Groove 2007 Migration Planning
• White paper: Phased Transition to Groove 2007
• White paper: Comparing Groove Enterprise Service with Onsite Groove Server Manager
MSFT TechNet has the White Papers for Office Groove Server 2007 here..
Chapter 11 of the eBook 'First-Look-2007-Microsoft-Office-System' has a nice introduction to the Groove 2007 application, which is now a part of the Office 2007 suite.
MSFT Midsize Business Center has some information on Groove and SharePoint co-existing together. It has been that way for a very long time - it was called the Groove Mobile Workspace
but a lot has changed since then.. Read on..