Parsing an external URL

I'm in the process of rewriting a site in PHP (as I learn it) to make it more robust. One of the functions I regularly use is calling an external URL, parsing out the data I need and saving that data for use on my site. (Don't worry, we've made arrangements with these companies!) I'm unsure which function, include(), readfile() or any other to use where I can go through the called page and parse out what I need. Example, let's say I needed to get the page's title, I would need to be able to go through the file and find an tag object, discover the tag is a <TITLE> tag, start gathering the text object until I reach a tag object of </TITLE>. If there are any tutorials on the subject, can someone point me in the right direction? Thanks! Mark mivaguy@comcast.net