The term you're looking for is actually called Screen Scraping.
One thing you have to consider about scraping web sites is that they are beyond your control and can change frequently and significantly. If you do go with scraping the fact of change ought to part of your overall strategy. E.g. you will need to update your code sooner or later to deal with a "moving target."
Here are a couple of C# links to get you started:
http://www.cambiaresearch.com/c4/3ee4f5fc-0545-4360-9bc7-5824f840a28c/How-to-scrape-or-download-a-webpage-using-csharp.aspx
