Shoutbox

I am making a script which needs a dynamic server with a website.
Sorry, thats a bit unclear.

The user would use dynamic generation, they could enter their email address for messenger and it would create a file like msgplususer@hotmail.com.jpg on the server. Then the script could fetch dynamic display picture updates.

What would I need to create such a server? I am trying an ASP.NET script, but would like input on the subject. Has anyone tried this before? Have you found a good method of doing so?