There are also a number of projects at Family Tree DNA for the various subclades of R1b1b2 such as R1b-U106, R1b-U152, R1b-U198, and R-M222. These projects can only joined by people who have undergone the appropriate deep clade tests at FTDNA to determine which subclade they belong to.
If you know of any other useful links or resources do let us know!