I bought the logitech G25 racing wheel two years ago expecting GT5 to be released soon. Here I am two years later and Logitech now has the G27 and still no GT5
here is the G27:
Amazon.com: Logitech G27 Racing Wheel: Electronics
But I must say that I have never had so much fun racing on my PlayStation (I've been using GT5 prologue)
The force feedback is very strong (You can't casually race a high HP car with one hand) but what I find the most incredible is the way they are able to transmit the feeling of the tires losing traction (understeer and oversteer!)
With a large enough screen and surround sound, it can get very realistic.
My only complaint is that in a straight line most cars give the wheel a strange "loose" feel and you are constantly compensating both ways to keep it straight. Oh! and the gates in the stick shifter are not realistic, But you have the option of SMG or wheel paddles to change gears realistically.
Anybody with a PS3 that likes racing simulators will really enjoy this. If like me, the only experience you have with racing wheels was playing video games in arcades in the 90's... you will be blown away!