One issue is providing the software to support collaborative
development, I have little advice to offer here except to
try it out and see what works. Evolve or change the
software if it seems to be a problem
Another issue is *WHO* exactly is going to be doing the
collaboration. From which follows how widely accepted the
results will be. This in not a technology issue and can
make a shambles of even the slickest technology....
My 2 cents are to try involve the professional societies, at
least here in the US, I don't know about elsewhere. One
very encouraging sign that health care oriented professional
societies might have the infra-structure to support such an
activity is the Hopkin's announcement of Medbiquitous.org.
http://www.medbiq.org/index.html
This group intends to be the infrastructure collabortive in
back of the community efforts of the societies themselves.