Here are a few links relating to collocation, thanks to Adrian Howard and others. If you know of more, let me know, please.
CSCW 2008 Workshop: Supporting Distributed Team Work
RE challenges in multi-site software development organisations
An empirical study of global software development: distance and speed
Team Knowledge and Coordination in
Geographically Distributed Software Development
How Does Radical Collocation Help a Team Succeed?
Working together in “war rooms” doubles teams’ productivity
George Dinwiddie Collocation Page