Help with Working with POST data

Hi All,
I have been given a project to convert a php page into an asp.net page to work in our environment. Someone wrote a flash app that post data to a PHP script that then writes a text file to preserve state (I know YUCK). Looking at their action script they are building what looks like an array to add like 50 things in and then calling sendArray.sendAndLoad("test.php", result, "POST");

My Question is that I need to build the ASP page to handle those 50 things that come over as a post, but I am not sure how to do that. I can't use cross page posting, page properities, and stuff I am used to doing. And all the tuts I see are based on that. So how do I work with raw true html post data.
Thanks in advance for your help

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