See Taskbarn, a free project management/collaboration tool.
I don’t know if this would help or not (and I haven’t played with it yet), but one of the challenges my online students in English 328 had this term was collaborating on the movie projects. I knew this might be tricky. I’ll post more about this later, but the short version is that it all “worked out,” but not without some challenges along the way.
In the end, the groups in both of my online sections mostly did face-to-face collaboration, which makes sense since at least 80% of the students in these online classes are currently taking class on campus. In fact, I think there were only two students in total who were really “distance learners,” one in another state a couple time zones away, and another in the military and stationed in the Middle East. Without getting into details now, people coped as best they could and it basically worked out about as well as the collaboration did in the fall term in the “normal” face to face class.
Still, I think that students really could/should be able to do the whole thing online by exchanging text, audio, and video. In theory, they could use emuonline for this, but it has some kind of clunky features in terms of uploading large files and such. So maybe something like this would work better.