Working together

How would i work together with a friend on a project? tryed a few ways including svn Assembla. Any plugins or software we can use? team of three.

http://va.lent.in/blog/2011/12/13/so-how-do-teams-work-on-a-big-unity3d-project/

http://answers.unity3d.com/questions/186421/how-do-teams-work-on-projects.html