HTTPLISTENER - decoding a client POST

I'm (trying) to write a simple HTTP server in VB.NET

I have it up and running using threads, seems to be working fine, serving up web pages and processing HTTP GET's

I now need to process HTTP POST's and I'm having difficulty - was wondering if anyone has some guides / tips

I think I understand that POST's are encoded by the browser and are received as such by HttpListener

How do you decode an encoded stream? Anyone?

Cheers