Virtually all of my flying is done online with Squawkbox.  This is the virtual ATC software that allows you to communicate with air traffic controllers and pilots online.  There is simply nothing else like it.  The entire worldwide ATC system is modelled and staffed by people that are enthusiastic about flying, but from the controller end.

Sqauwkbox is free and written by my good friend Joel De Young.  Joel was kind enough to implement features that enable the Squawkbox to work in a real cockpit environment

Myself, Ben Supnick, and Joel De Young after a day of development.