How to post to Facebook user's profile?

On my site, user's post goods for sale (similar to Craigslis). I want to create the capability for user's to have it post to their facebook profile automatically from my site.

The scenario I'm imagining is this.

User creates an account on my site. In their profile, they allow my site to post to their facebook profile. From then on, anytime they post an ad, it automatically posts it to the facebook profile as well.

1. What do I need to do to create that agreement between my site and their facebook profile?
2. How do I actually post it to facebook? I'm developing in .NET/C# on ASP.NET MVC

Been hearing multiple stories on how to do this, not quite sure which to take and开发者_Python百科 run with. Thus, I'm asking the experts here on StackOverflow! Thanks in advance!

A few resources that you might find helpful to get started :

Facebook Developer Site - Documentation for the API, forums, etc.
Facebook Developer Toolkit - a .NET library that provides access to the Facebook API

If you're looking to provide integration with facebook features on your site, you might want to look into Facebook Connect and its capabilities..

A while back I was looking at Facebook Connect and ASP.NET MVC and found these links helpful as well:
Making Facebook Connect work with ASP.Net MVC
http://singulartechnologies.com/integration-of-facebook-connect-with-asp-net-mvc
http://singulartechnologies.com/custom-asp-net-mvc-authorization-with-facebook-connect