If you're a member at REI, they have classes in just about anything you can think of. Most of them are free. The ones you pay for are the ones that involve an actual outing (some are overnight).
North of the border we have MEC. I worked their casually for a few years. Tons of fun. I usually point people to this link -
Hiking and Camping Information - Mountain Equipment Co-op (MEC). Free Shipping Available.
You can find it under the LEARN heading on their home page, top right.