Ann Bares, at her blog Compensation Force, has a great post about pricing jobs in different geographical locations. This is an issue that many an HR person has struggled with if they have multiple locations. Two people doing the same job, requiring the same skill level, however, they are located in two different geographical areas, of which one is more expensive to live in than the other. When this happens there is pressure to pay the one more than the other. And the basis that is often used is Cost-of-Living.
Ann suggests that rather than using cost-of-living it would be more effective to use cost-of-labor as the more appropriate measure. She gives several examples of places that have high cost-of-living indexes but lower cost-of-labor indexes. So check out her blog, by clicking the link above, and get a better understanding of this effective way of pricing a job.