I have to admit to being somewhat of a chat hall junkie, and I have found a number of chat sites which support my various interests. Sometimes the best way to learn is to put down the books and listen to (or, in the case of the web, read) other people. Here I have listed only sites with a specifically chat hall style, not message boards. reason for this is purely personal: I don't like or use message boards and find them to be largely frustrating and a waste of time.
Clicking on a link will open that page in a new browser.
This chat hall hosted by garden.com had the advantage of being fairly busy. One may have to be a bit assertive in order to join the conversation, but the regular chatters are usually willing to answer questions or exchange observations. This site accomodates both Java and non-Java browsers.
WBS is a chat site with numerous different halls on different subjects. Although some people find this site difficult to get the hang of, it's worth learning to use if you want to interact with other gardeners.