Option one, there should be some free sites available but they will give you popups or advertisement etc. (i dont know any good sites for that, maybe others do)
Or get a free hostname at
www.dyndns.org (like bbclan.kicks-ass.net) and point it to one of your members ips where he can setup a webserver. This might be slow depending on the connection.
Or you get a fully webserver with domain name but thats $$.