Just do it!
If you can read this blog you have enough technology. The technology isn't important
Find a service that provides social network hosting or blogging . The application isn't important. Popular ones are Facebook (feel free to send me a friend request), Ning, Google groups, Yahoo groups
Everybody gets hung up on these first two steps. The internet is full of blogs and communities with one or two posts.
A personal example - there is a Facebook group justenoughtechnology just waiting for people to join. Please drop in
It is you that is important. You must be passionate, persistent and have a life outside the internet. If you don't have all three of these characteristics your on-line community won't work.
It really is as simple as that. Enjoy what you are doing and send me your success stories