Check whether such a group already exists, see here, search on the internet (keyword will be your place name + lug/glug/fsug). And if you find one that is not listed here please add it so that others can find out it easily.
Find out who are interested, ask your friends, colleagues, classmates...
Announce a meeting (use your notice board, class room, or wherever people get to see it).
Discuss with them their interests, share experiences and how can you help each other.
Collect their contact inforamation.
Also you can create a community in online social networking sites like Orkut and link to your mailing list in the description.
Also add all the details about your your community here and use that page for co-ordinating with the team, say for arranging a meetup, want to conduct a poll ...
Conduct regular meetings and discussed the new exciting things you have done.