Just an update, I've been looking at doing collaborative stuff over the internet recently, and it's quite exciting what's out there at the moment. Here are a few I've found :
This is kinda close to my heart as indaba means "discuss" in ndebele/zulu so it has a african feel to it right away ... I mean this in a good way :) ... anyways it seems more geared toward remixing ... several competitions with Name artists 3eb, K-OS, etc. but regular musos are very welcome ... I've seen Vernon Ried, (from Living Color ... one of my favourite bands) wicked!
Anyways here's my profile
Basically you have what are called sessions, you can preview whatever the owner feels is a good example of the song, if you like it and are signed up you can then download whatever is available to work on, bring that into your own DAW (Digital Audio Workstation ... Cubase Reaper GarageBand Pro-Tools etc.) and submit an audition, once accepted the rest of the tracks / mixes are then unlocked for you to contribute further.
There is a limit on how much you can download per month (this is very african) you can pay for more.
It also has a shout box to allow members of the session to communicate nicely.
This site took me a little longer to figure out, also a very vibrant community, also running remix competitions (eg. Rudy Sarzo - Quiet Riot, Ozzy Osbourn)
It has quite a bit more AJAX (web2 technology) which IMO is a double edged sword, anyways they have various projects which again you can preview, but once you're logged in you can download any available track (ie - no audition) to start with it's best to get the lot as they are zipped together along with license notes (Creative Commons).
Once you are in the detail of a project you can preview any of the tracks uploaded so far, and for each track there is a play, download and comment count, there is also a recent activity box and a forum dealing with the project.
Again you're expected to do your own thing with the track on your own DAW but there is a sync track they recommend you use to keep things together ... seems to work nicely except that they use a sine wave, I've since made my own (version1..0) using a square wave pulsing A440 @120BPM, this should [being square] match up much easier.
One other nice thing is that they've incorporated google maps so you can see where the other members are from.
Anyways here's my profile:http://www.kompoz.com/compose-collaborate/profile.member?memberId=7895
This was the first collaboration tool I looked at, but then I was searching for collaborative music software as opposed to a site, so this is a 98MB download before you get started, the T4 is free, but they >>really<< want you to buy the full version, it's tied in somehow with the Line6 POD, which I don't have, but it does give an indication of quality.
Anyways, first you download the software (PC or Mac ) and register on the site ( I'm at http://www.riffworld.com/Members/hiphophippie) then fire it up. Basically it's a simplish DAW that works around phrases, (riffcasts) as these are short and centrally stored in it's own format it can be near realtime with your riffcast appearing to all logged into that session pretty soon, this (riffcast) can then be looped, mixed whatever with results being available to all quite quickly.
This does however have a SERIOUS BUG unfortunately, in that you can't save the raw data, you can export the mix, but the riffs are kept online. (as far as I can work out)
On all the sites the folks are friendly (so far), encouraging and range in style and competency so you can find your own level and learn from all around.
Creative Commons seems to be the license of choice when there's one to choose.