You can also put the session key (as long as it is not predictable, e.g. an MD5 string) as the top directory in your URL:

   http://your.com/14681655ef653af/home.html

The advantage of this approach is that if you make all of the links in your HTML relative to each other, you don't have to do any URL munging inside the HTML. Of course, you can forget about getting meaningful caching of proxy servers or browsers.

The session key is easily obtainable with mod_perl or rewritten using mod_rewrite.

Liz