I learned to boat up there in central NY. Its just awesome. There are a number of spectacular runs in the area. Some of my favorites are Bottom Moose, Fish Creek, the Raquette, the Grass (Twin Falls) and the Oswegatchie. American whitewater has good content on NY rivers check it out:
American Whitewater - NY State Rivers
as for the forum to find people to boat with check out:
The great part about fall is they lower the reservoir water levels to their winter levels and release the water for boaters on the weekends. So your always have water and if you show up to a release there are always 50 people to boat with. Also and maybe my favorite part is you can run some crazy ass shit b/c lots of drops end in a huge pool...f up and you end up in a lake. I really can't say enough good stuff about NY boating! If you get the chance go to moosefest is one hell of a good time!