Mobile Workforce State Income Tax Fairness and Simplification Act - Limits state taxation of the wages or other remuneration of any employee who performs duties in more than one state to: (1) the state of the employee's residence; and (2) the state in which the employee is present and performing employment duties for more than 30 days. Exempts from the definition of "employee" for purposes of this Act a professional athlete or entertainer or certain public figures.