Parsing with PHP Tutorial?

I want to how to parse a webpage using PHP. For exaple i what to use php to look at a url such as yahoo.com and extract the infomation that i want from it and display that information on my page.

Where can i read a good tutorial about this?

www.thescripts.com has a tutorial like that in its php section.

here are some scripts that do this for you, I'm sure you could view source and learn a lot.
http://www.hotscripts.com/PHP/Scripts_and_Programs/Web_Fetching/