Requires server side scripting to control the membership, and send the
emails.
Which path you take depends on what your server supports (asp, asp.NET,
PHP, Perl, with Access, MS SQL Server, mySQL database) and your
programming skills.
For a Windows server supporting asp and Access database see:
Protect individual pages: (Requires Windows Server with support for ASP
and Access database)
http://support.microsoft.com/default.aspx?scid=kb;en-us;825498
for the password system and search for CDOSYS for sending emails -
though check with your host that these are supported.
For Unix look for a PHP with mySQL solution.
If your host supports FrontPage extensions with subwebs and unique
permissions, and you are willing to allow your users to share password
and userId information, then you could use FrontPage features for the
login: see
http://support.microsoft.com/default.aspx?scid=kb;en-us;301554 (FP2000)
http://support.microsoft.com/default.aspx?scid=kb;en-us;825451 (FP2003)
(but I would avoid this, since a shared password/userid can get loose
easily, with the problems of changing it and informing all other
members). Sending the email will still require server side programming.