I recently registered at PeerTrainer.com (w/f/s). It is a website originally intended for people to collaborate about their weight loss plans, but I am using it to keep a journal about my weight gain goals.
If there is anybody who is also a "hard-gainer" looking to put on pounds of lean muscle with me, let me know and I will send you an invite. Or you might be able to join yourself with a little searching. The name of the group is Hardgain Allstars, and my username on peertrainer.com is bluefanta.
I think the groups only allow up to 3 people, but basically we'll be able to motivate and push each other to exercise right and eat healthy.
I'm a 20 yr. old 5' 11" male weighing in at 150, my target is 170 in at least the next couple years, but hopefully around 12 months I'll be close to that weight.