User Logon Information - Tough Question requires whiz

[RPBLEA]

I'm running a database that records cable information on a major network. I'm running a gui interface in the .net aspx web form, I'm running the page in aspx and was wondering is it possible to record the user logon name that is accessing and making changes to the gui interface through aspx? How Can I do this? Can anyone supply code, cause I have no idea? clueless here!