Just spotted while trying to use meta-course enrolments in 2.0, that actually most of the enrolment methods we have enabled are unavailable!
Manual enrolments, category enrolments, self enrolment and guest access show up under "Enrolment methods" for a course, but "External database" and "Course meta link" do not. Those are definitely enabled under "Manage enrol plugins", though. The exception to this is courses that were created before the Moodle 2.0 upgrade, where modules that had those plugins are still using them.
Any ideas, anyone?