Phidget has a very comprehensive code base for interfacing with their RFID reader and other products at
http://www.phidgets.com/programming_resources.php[
^] that uses .Net as well as some ASP.NET with Active X control that only works in Internet Explorer. Google Chrome, Safari, and Firefox don't support ActiveX.
Microsoft BizServer RFID functionality is pretty simple to set up and use --if you have the software.