This site is an excellent resource for all heli mods based on MS's Flight simulator
http://www.hovercontrol.com/ It can help you find online communities that operate with full radio communication's with human control tower operator's.
For heli flying, with mods Fs2004 is more realistic atm than FSX with mods.
Dodosim has what is considered the most realistic flight model mod, it's the Bell 206. They are working on a Huey and R22 that should be just as good.
You can also download the free X-Plane ver9 beta. It's alot better for heli's than a default install of any MS Flight Sims.