It's going to be very tough to control wheelspin with the Dualshock, because you are limited in your ability to control the throtle.
Basically, you don't want to just give it full throttle all the time, or you'll just spin. You want to give it enough to where you can *feel* it is about to slip, but you have enough traction to accelerate. All of this is hard to do without a wheel though...
In your A-Spec races do you race with traction control on? If so, I recommend you turn it off anf run some laps in a RWD car in order to get the hand og driving it. Once you practice launching, and everyting else, you'll do much better. Practice is the only thing that will really help.
Parker