ok, guess you're going to have to specify what you want to do..
Perl & PHP are very similar, both are rooted in C programming (As you probably know)
they Can talk to one another, it's a bit difficult, btu they can.
I'm actually prefering PHP over Perl, due to it's a lot easier to do things in PHP with it's built in functions (mail for one)
but if You want a Perl script to call a php script, or include it that's a bit more fun.