Hey Matt.
I did a google search for "ectomorph" and came up with this article from bodybuilding.com that should point you in the right direction:
http://www.bodybuilding.com/fun/jon11.htm
At the end of the day, it's very difficult to drive against your genetics. When I was about your age, I'd work out alot and I'd eat like a pig, but I still wouldn't make the physical type of gains that I was looking for. I had the metabolism of a hummingbird, and anything that entered my stomach instantly vaporized.
It's funny - now that I'm older and my metabolism has slowed down, I'm able to put on the pounds like I never could 10 years ago. So moral of the story - work on it, but at the end of the day your body will do the talking.