Just bought a new curve, and hadn't thought through the implications regarding my ProClip device holder for me car. I just upgraded from an 8700, and the Curve doesn't even come close to fitting in it.
I had recently stopped using my ProClip 3G iPOD holder because of issues with how the lower mounting adapter had with my Accord.
Anyway, while not snug, the iPOD adapter absolutely works with the Curve.
Obviously ProClip will eventually release a Curve specific holder, but if you can't wait (and I use my car holder every day and can't really live without it), this is an option.
ProClip 3G iPod holder