Blue Shift Coop v2.0 Beta is now available for download at the 'Download' section. I said somewhere at the [HLCoop] forum that it would be released before the year 2010, so I hope you don't track me down and kill me for being a liar :-)
This is only a beta version, so if you encounter any bugs or problems, please report it to me at firstname.lastname@example.org and I will fix it in the stable version if I'm able to.
Blue Shift Coop v2.0 supports max 6 players. If you and your teammates wants to be unable to hurt each other, be in the same team. You do this by having the same models as your teammates.