To answer the original question: the flight simulator that comes with the Falcon 3D is FMS, which is a freeware flight simulator. A number of RC aircraft include a copy of FMS in the box. You can download your own copy from here: http://n.ethz.ch/student/mmoeller/fms/index_e.html . You'll still need to buy some sort of cable to hook your transmitter up to the computer if you download FMS, but the Falcon comes with a cable.

While FMS is certainly a lot more useful than nothing, it's not nearly as realistic as the good commercial simulators. FlyinTiger listed most of the good ones. Another is [link=http://www.phoenix-sim.com/]PhoenixRC[/link]. Most people who've had the chance to compare it to Reflex seem to consider Phoenix to have the more accurate helicopter flight model. It's new though and doesn't have as many features as Reflex.