Just a short post to tell that I have replaced the source code with the VS2008 RTM version :http://blogs.msdn.com/mitsu/archive/2007/06/21/how-to-implement-a-many-to-many-relationship-using-linq-to-sql.aspx

To answer to some people having issues, this solution allows to browse between entities using a many-to-many relationship with code or databinding but not to use this relationship in a linq query !!