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