I've just been introduced (by Bee) to Web Collaborator, which omtegrates a blogging tool. It looks like a really exciting and useful tool,and I'm looking forward to trying it out. Here's what they say about the blog bit:
"Discussion Through Blogging
The discussion section of any collaboration is done in a blog. Descending from the words 'web log', a blog is basically a journal that is available on the web. Postings on a blog are arranged in chronological order with the most recent additions at the top.
A blog is a perfect arena for discussions where you can attribute who is saying what and when they said it. This allows a group of people to focus on certain parts of a collaboration. For example, if I noticed that a paper we were working on needed more citations, I might say so in the blog. It is the first page people see when they come into a project, so any news of interest that might be inappropriate inside the project should go there. "