LISTEN/NOTIFY

I'm developing an e-commerce site using Apache/mod_perl and, for
performance, I intend to cache rows such as user and product information
inside Perl. I think the LISTEN/NOTIFY interface would be perfect for
invalidating the cache when a product/user gets updated, yet I have not
found a way to access it from Perl -- DBI, or DBD::Pg even, offer no way
to "listen". Also, I don't really like the vanilla Pg. So, my question
to you is, is there another efficient way to accomplish notification of
updates?

Thank you

Cristóvão