There’s a lot of excellent, practical discussion taking place right now in the Enterprise 2.0 Conference Community site. I’m following two threads in particular: 

• Building the Business Case for E2.0  
• Barriers to Adoption for Enterprise 2.0 Initiatives?

Regarding barriers to adoption, Sage Advice on Wiki Adoption: The Pitfalls is a recent post with my take on how to avoid and overcome the barriers to wiki adoption, many of which are the same barriers to adoption of the larger Enterprise 2.0 idea. Nate Nash & Jay Hariani recently wrote about their work internally at BearingPoint. Jon Mell outlines his 9 principles for wiki/Enterprise 2.0 adoption.