Add a symbolic link to your homepage file.  (man ln for details)
Use your login name as the file name.
You can insert files into this directory but you can't change them
or remove them.  Send mail to adamb@cs.cmu.edu if you need to remove
a link.  

YOU SHOULD ONLY PLACE LINKS IN THIS DIRECTORY, NOT FILES.

Example:

% cd /afs/cs.cmu.edu/academic/class/15847a-s96/web/students
% ln -s /afs/cs.cmu.edu/user/adamb/web/adamb.html adamb.html

Then try to test this by opening your new URL as:

http://www.cs.cmu.edu/afs/cs.cmu.edu/academic/class/15847a-s96/web/students/adamb.html