Everything that can be done in php can be done by perl. Period. Plus lots of things php can't do.
(Off topic rant: i recently got into an arguement with someone over php vs perl, and his arguement was that php was better b/c you had to reinvent lots of wheels, as all you had to do in perl was just download a program and fill in a few variables. This person was inordinately proud that he just spent the last 2 weeks writing a templating system.)