Perl isn't nessacerily outdated. It hasn't seen as many revs as other languages recently but that is because it's an old language when compared.
There are still somethings that perl will do that PHP won't. I just recently ran up against the need to tell if something is uploading how much is done. In PHP there is no support to read raw post data. To do this in php would be riduclous. Perl on the other hand has no problem.
Perl also has many scripts available for use where newer languages have many but not nearly like perl.
I'm not avocating learning Perl, I'm just correcting the statement it's outdated. Saying it's outdated is saying ISO C++ is outdated.
If I was to tell you a language to learn for internet programming I would be biast and say PHP. But to tell you the truth they all have there nice features. I like ASP especially if you know your clients will only be using internet explorer, there are some amazing things you can do really easily with that windows server/sql server/internet explorer framework.
Coldfusion does some neat things to, along with JSP.
I would say pick one. Then open up the newspaper and see if there is anyone hiring and be your own judge if you've chose right.