Let me add, our group's website is at:
http://www.madisonreef.com
Normally we meet at a member's house [rotates among volunteers] monthly for an informal gathering. It's a fairly loose group, but a growing one, in the Madison and Southern Wisconsin area.
At present we have no dues or such, though normally beer or other refreshments are appreciated [as are frags].
Come to a meeting, contact some others through the club ... I know personally I've met some wonderful people, gotten really nice frags, and learned a lot from seeing all the tanks, meeting other reef people.
Hopefully we'll see you at a meeting.