The first one that came into my mind was the Hobby Greenhouse Association.
They used to have a listserve type email list and a bulletin board. Here's
the link to their page. http://www.hobbygreenhouse.org/

I used to take their newsletter, but ay that time it was geared to vegetable
growers and I really didn't care about hothouse tomatoes.

Do a Google search and your'll find others.

K Barrett

"tennis" wrote in message
...
I've heard of such a site and as my planning for a greenhouse shifts
into high gear, would like to check it out. But I can't find it. Anybody
know anything about it?