PHP and ASP are specialized languages, designed to ease and streamline certain areas of programming (Web). Perl is a general language that can be used in just about any field, and a very powerful one at that. But, with its broadness and power comes a level of complexity greater than that of specialized languages like PHP and ASP. I don't consider it hard, though. Then again, I've always been programming in it and I guess if it is hard I'm just accustomed to it and don't recognize how difficult it is. Perl is far from dead, in the end it will probably out live all of 'em.
If you learn Perl you'll know PHP, they're essentially the same language with only a few major differences.