There are a few decent ones. Mel Bartels has a mail list (it's not a Yahoo list so it's still quite good!) and there's the newsgroup
sci.astro.amateur for another. There are other forums, often with a particular club's pages but they tend to be a bit less popular as the newbies don't usually find them and the knowledgeble posters tend to not attend unless they are members of the club.
Be forewarned that if you go on Mel's list, you will be getting quite a few emails a day unless you go with the digest version of the list.