I know that HB isn't the best place to get critique. But as far as leaning goes pretty much any forum. If you have Canon join POTN I find them to be pretty useful and even if you don't have a canon camera they still are pretty useful. But if you are looking for critique on photos try joining an art forum that has a photography section... it's different getting critiqued by a wedding photographer vs. a real artist who understands a ton about composition (that isn't to say the photographer wouldn't understand composition.. I would just assume an artist would have a better eye for it, not trying to start a fight).
I would recommending googling tutorials as they are also pretty helpful. Oh, and READ BOOKS! That helps a ton.