StackExchange has a useful thread on how to keep up-to-date with the F# community, some snippets from the answers below
Richard Minerich's blog is good: http://fsharpcentral.com/. Every week he publishes a very comprehensive "F# Discoveries This Week" post.
The forums at http://hubfs.net/ have been active since the early days of F#, although IMO there's enough critical mass on Stack Overflow to make it worthwhile asking F# questions there.
I recommend http://tomasp.net/ which is run by Tomas Petricek. He is a very active use over at Stack Overflow for the F# tag. Actually he has answered a good portion of my F# questions.