We're looking into deploying Sharepoint 2007 and are considering My
Sites as a tool that would allow our students to easily create their
own sites.

I'm looking for suggestions on how to deal with this scenario: A
student creates a site for some external club they're in. They would
like to give access to members of this club to post in the site's
forum or upload documents. However, these external people won't be
valid users in AD. I've read some stuff on extending the web app so
that it can also authenticate users against other sources but I'm not
sure that's exactly what we want. Ideally, the site owner would be
able to manage users for their site without intervention from the IT
department.

For comparison, we currently allow students to host sites through
Apache and they can perform something similar to this by setting up a
.htaccess file. Is there any way to do something simple like that
with Sharepoint? Any suggestions are welcome.