Group email solution for website

i need to create a solution to send email to 20 members from one address. I know yahoo groups can do this, but i want something that i can implement on my domain. Is there sucha thing, maybe open source?

Personally, I use a Forwarder. I create a forwarding address at my domain with an obscure name, and I email myself the message and put that obscure address as a BCC so nobody sees it. The catch is that you can’t forward to comcast and/or AOL.

There are also Announce and Discussion lists. Announce is a more straightforward way to do this and can go to AOL and Comcast accounts, but it uses a web frontend, rather than email. Discussion can be rigged so it’s outgoing only from one specific address.