Publicly Available Email Groups that span ISPs?

This is post number 1,500 to my blog. I am on the board for our homeowner association. Actually I am the Secretary so I maintain the association web site.

We have a community phone/email directory that our members can access. It is available in PDF form or Excel spreadsheet. I use it to send out bulletins to our community. For my own use, I have created an Outlook contact group so I can easily email all of the community members. Any time one of the townhomes is bought and sold, I update the directory (PDF and XLS) as well as my Outlook contact group. Other residents who also wish to email the community use the spreadsheet I maintain and post to the site to update their own Outlook contact groups. Surely there must be a better way.

Autodesk Labs has various email groups, e.g. [email protected]. When customers email this address, their message goes to a variety of people associated with the technology preview: developers, testers, product managers, VPs, etc. I maintain these Autodesk groups that are hosted on the Autodesk Exchange server. I want the same thing for my homeowner association. Is there a service where I can create email groups that anyone can email to? My personal ISP is comcast.net, and from what I can tell, they do not offer this. As you can imagine our homeowner association consists of residents spread among many ISPs.

Inquiring about available group email solutions is alive in the lab.