Dear community, what would you recommend for mailling lists? The conference is non-profit, named Smidig2010 (=Agile2010 in norwegian), will have about 400-500 participants 16.-17.november. At the time of writing this, we have not opened for registration, but would like people to be able to participate, ask questions, get informed and get inspired. We've used a forum before, but forums don't seem to be a good fit for this. I would like to set up a mailinglist, It'll have to be KISS, for the users:

1. enter your email (a input box at our site smidig2010.no)
2. get a confirmation mail, click a link.
3. start posting, reading through archives, answering others etc.

I like the look and feel of googlegroups, but I don't like the signup/account creation overhead imposed on the user. I've heard you may combine googlegroups with mailman and stuff, but, yeah, I can't believe our own incompetence on this subject! Btw, we are mostly developers and the conference app is being written in ruby on rails.

Being non-profit, we prefer free, but we take everything into consideration. Any suggestions?