Rather than use threads, I've been using a drop in replacement : forks. I am so far happy with it.
http://search.cpan.org/~rybskej/forks-0.34/lib/forks.pm
From the POD :
The standard Perl 5.8.0 threads implementation is very memory consuming, which makes it basically impossible to use in a production environment, particularly with mod_perl and Apache. Because of the use of the standard Unix fork() capabilities, most operating systems will be able to use the Copy-On-Write (COW) memory sharing capabilities (whereas with the standard Perl 5.8.0 threads implementation, this is thwarted by the Perl interpreter cloning process that is used to create threads). The memory savings have been confirmed.