How to create a multiplayer game for steam using flash/flex?

Hi guys,

We've got a multiplayer game ready to go. Currently it is not multiplayer, but we'd like to get it to a stage where it can be played over the steam network by users of steam and owners of steam games.

We'd like to if anyone could briefly give us a breakdown of how to get out game up on steam and available for multiplayer?

Does steam host servers, and can we utilise a steam server to transfer data between players or would we have to run our own server?

Currently were using flash builder to publish via adobe air to a windows desktop exe. Can anyone briefly explain how - once a player has downloaded the game from steam we can connect two players? Does anyone know how to use actionscript 3 to access steam network?

Anyone have any experience developing multiplayer turn based game for steam using flash /actionscript 3 /adobe air?

Thanks for your help in advance,

i