VB.Net Multithreaded Web Scraper

I need multithreaded VB.Net source that scrapes like this: 1. Pick urls from a list (can be from a list of any kind - you make it up. From a text file or an array or a database - not important) 2. Go and scrape each url. No need to save the contents of the scrape - I am just interested in the overall logic and how the multithreading works. I'd like to be able to set the number of simultaneous threads. The scraping should show how to use the most basic scrape (i.e. no javascript support) as well as using Watin - both in multithread. I already know how Watin works - I've just never multi threaded it. If you plan to use any commercial library, I need to know beforehand so I know the cost. I use Visual Studio 10 and Windows 7 x64 and the source must run on this.