Ive done a workshop (Popular Photography) and am signed up for one in February (David Mecey). Neither is for weddings though. The one that I attended in Kentucky was awesome. One of the instructors was extremely helpful. After shooting stuff for years I came home learning quite a few things. Monte Zucker is supposed to be an awesome photographer. If you can afford it, I think it's worth going.
A real good one is done by Blake from artists and associates, see www.photographer.com I had a total change in my business practice after attending one this summer