First, I need to login in php page, then I'm redirected to a necessary php page which contains some text I want to parse. Is there any tool to do that?
Thanks.

Well, when you enter into any sort of HTTP exchange, you really don't know and you really don't care whether the information you're seeing is being generated by a PHP program or not. You see only the HTTP data-stream that the PHP program produced.

Yes, in a variety of languages such as Java, Perl, Python, and I believe PHP, there are classes and objects which know how to carry out an HTTP exchange with a client.

These languages also have a variety of general-purpose parsing and text-grabbing facilities, which are often described under the somewhat peculiar term "regular expressions," sometimes abbreviated "regex." This is a dollar-and-twenty-nine-cent word for "text pattern matching." It's something the Unix environments are quite famous for.

Your programming will be made considerably easier if the PHP program in question can generate an XML-formatted output.