When I was running xp-dev.com's beta, I used a collection of hand rolled scripts and mailman http://www.list.org/ http://www.list.org/. Personally, that did so

When I was running xp-dev.com's beta, I used a collection of hand rolled scripts and mailman http://www.list.org/ http://www.list.org/. Personally, that did sorta work for me. I had about 1000 beta users, and did not care too much about conversion ratios (downloads, CTR, new user signups, etc). I just wanted to get the word out when something changed. But, had I wanted to be more scientific, something like Mailchimp should do the trick.