Phil Agre‘s Networking on the Network contains plenty of great advice on academic networking — building a net of colleagues and collaborators. See also interesting related materials here, here, here and here. As for collaboration per se, see the links in my post on writing. See also this post at SBS on the conference networking.
Is there an academic counterpart for social networks like the Facebook? Yes. I have found Academia.edu, and there is plenty of sites of this kind (the Nature Network is just another example, and the Researchgate is yet another)