That's a lot of jumbled questions, Jim.
There are a lot of different ways to do this.
If you really just need one request create an ASHX handler and use JavaScript Serializer. Otherwise I'd recommend you look at using ASP.NET WebAPI. It's designed for REST services in mind and can get you your data in a number of different formats. MVC also works with automatic support for JSON results.
Here's an intro/overview article on WebAPI I wrote that gets you started:
http://www.west-wind.com/weblog/posts/2012/Aug/21/An-Introduction-to-ASPNET-Web-API
+++ Rick ---
What is faster at serving up JSON in .NET a Web Service or some sort of REST service for taking in AJAX requests then spitting out JSON? We have VS2010.. I haven.t used C# for some time.. I'll be using JavaScript in VS2012.. All I need is probably a 1 page "filename.aspx" to take request.. do the query.. spit out the JSON..
I guess with REST I really dont even need a page.aspx... Just some sort of listener? IHttpHandler? on a \folder...
Thanks
Jim