|First, the mandatory question since you don't mention it in your post:
What have you tried?
I remember I did something kind of like what you want about a year ago, since I didn't have a clue, I googled (don't remember the specific query), and one of the first links was a MSDN page with an example to it.
What I mean is: please show/tell us what you've done, and what is the specific problem that you have, so we know that you are indeed making an effort and not just wasting everyone's time.
Now, I'm not just gonna lecture you and give you nothing. Look for info on:
How to read/write files in C#
How to get the HTML contents of a web page
You'll need to get acquainted with the following namespaces/classes:
If you think you can do a thing or think you can't do a thing, you're right - Henry Ford
Emmanuel Medina Lopez