Yes, but not Linux (despite the similarities) and that's a fact, jack.

EDIT: Here's a thread on Nvidia's own developer boards to prove it. Disappointing, eh? Admittedly, the thread is a little old, but as the last poster said, there were no plans to add GPU support to the Linux SDK and it's stayed that way the last two years.

You can also see it on wikipedia:
http://en.wikipedia.org/wiki/PhysX