I agree with applicantguide, once you finish you boards you can practice anywhere including California. In fact, most of the IMG practicing physicians in California have in fact finished their residency somewhere else and then returned to California for practice.Thanks, Sabio and ApplicantGuide.
I have another related question:
If I do residency in a certain specialty in an IMG-friendly state, is it then possible to practice in a state which is not IMG-friendly, e.g. Cal? Is this a difficult process? I have a green card, if that is of relevance.