I don't think they're selling well, at least not in the Seattle area. There's a new red one at my local dealership that's been marked "Sale Pending" for at least 6 months now, and they just added another new one to their inventory. I'd expressed interest in one a few months ago, and got the impression that I could have a new one in 6 months at most.
I've decided to wait for the 458 Spyder, which I've heard will be available in the US by summer 2011. So, beans and rice only for the next 18 months.