ORIGINAL: fozjared
realflight and sms (the free flight sim downloadable online(google it))are the only sims i have experience with and realflight just beats the pants off of sms, but sms is a great trainer and you can get a usb radio on ebay for around 25$ and you can learn to fly simulator style for 25 bucks or you can opt for h9 fsone or realflight for 200$ and really knock some time off of your training period, either way sims are a super way to learn the basic physics of flight as well as stick movement etc. but it is like these guys said parkflyers teach you bad habits that you then have to unlearn, but they do help better than nothing i can guarantee you that! its up to you really, good luck!
That free simulator would be FMS not SMS and you would need to buy a cord to hook your transmitter to the computer.
I used Real Flight simulator myself and it cut my training time in half, used in conjunction with an instructor it is a very usefull tool and worth far more than the retail cost. It is also good for practicing aerobatics before trying them with your real plane.
From what I have heard the Hanger 9 FS-One is a great sim but I haven't tried it myself.