Apache::SessionX extents Apache::Session. It was initialy written to use 
Apache::Session from inside of HTML::Embperl, but is seems to be usefull 
outside of Embperl as well, so here is it as standalone module.

Apache::Session is a persistence framework which is particularly useful 
for tracking session data between httpd requests. Apache::Session is 
designed to work with Apache and mod_perl, but it should work under CGI 
and other web servers, and it also works outside of a web server 
altogether.

Apache::Session consists of five components: the interface, the object 
store, the lock manager, the ID generator, and the serializer. The 
interface is defined in SessionX.pm, which is meant to be easily 
subclassed. The object store can be the filesystem, a Berkeley DB, a MySQL 
DB, an Oracle DB, or a Postgres DB. Locking is done by lock files, 
semaphores, or the locking capabilities of MySQL and Postgres. 
Serialization is done via Storable, and optionally ASCII-fied via MIME or 
pack(). ID numbers are generated via MD5. The reader is encouraged to 
extend these capabilities to meet his own requirements.

WWW: http://search.cpan.org/dist/Apache-SessionX/