Lest this be considered a stealth advertisement, let me state up front that I work for Aerosimulators. We make a device that uses MS Flight Sim 2002, and have received approval for it as a Flight Navigation Procedures Trainer Level II.
It does have a lot of use for VFR training, learning to hover, navigation, autorotations and so on. It will not totally replace the real thing, but it does reduce the steepness of the learning curve.
I have to echo the comments on X-plane - the helicopter model is very difficult to use. The approval from the FAA was only for a fixed wing version, if I'm not mistaken. I believe there was a device that used X-plane that got a Level 3 FTD approval, but haven't heard much beyond that.