It's been tested against WP 3.0, but not specifically 3.0.1.

3.0.1  is classified as a very minor update, so I doubt there would be any problem.  It's likely composed of bug fixes, rather than new function designs.

Market Theme is built to be forward compatible, so there shouldn't be many issues as new versions of WordPress are released.

Plus, you can be confident that if there ever were any Market compatilbility issues with WP, we'd have a fix out within a couple of days tops.