It's this one:http://www.gameracer.co.uk/detail.aspx?ID=3
Used this for a whole DAY on GT4 on the PS2 with the Logitech 900 degrees wheel and pedals (Escort Cosworth around Nurburgring), and it was brilliant, until the wheel burnt out and I couldn't play it again.
It is fully adjustable, you clamp the wheel on the middle bit, and the pedals on the lower bit. The seat is a proper Corbeau thing. Buy a Force Feedback with this and it's really good fun.
Would be ideal with new Forza 3???
The whole thing is clean, it's in typically unused condition, and has stood in my loft (in a smoke free, clean house) for about a year.
Excuse the mess, it's the loft.