Please see my comment to the question.
Using
HttpWebRequest
you obtain a document. If this is a HTML document, you will need to parse it. It would be good if this is a document well-formed as XML, then you could parse it using one of .NET XML parsers. Not all Web pages are like that, unfortunately, so you may need HTML parser which does not require well-formed XML compliance. Try this one:
http://www.majestic12.co.uk/projects/html_parser.php[
^].
This is, by the way, is called
Web Scraping,
http://en.wikipedia.org/wiki/Web_scraping[
^].
—SA