I started learning PHP and I was able to get myself familiar with it. Now, I want to explore other programming languages like PERL so that I can compare it myself to PHP. Will I be confused to learn two language? Or are there any disadvantages?
I would spend some time getting decent at your first language, but once you have done that start exploring. There are a lot of languages out there and a lot of them are nicer then PHP or do something better.
I would take a look at the book "Seven Languages in Seven Weeks" which will walk you threw Ruby, IO, Scala, Prolog, Erlang, Clojure and Haskell which will make you learn a whole bunch of new ways to code.
Short Answer: If you’re just starting your programming career, then I would advise you to focus on learning just one programming language at a time.
This is because there’s little to be gained by listing many programming languages on your resume without really being good or highly skilled in any of them!
As a general rule, it’s far better to learn one programming language and master it well before learning other programming languages.
I too started out with PHP. It's a good first choice as there is a pretty large community, and there is a good chance you can pick up a job writing it.