Section 114 of Public Law 110-315 (the so-called "Higher Education Opportunity Act") took effect on 01 July 2009 and affects all military personnel, their spouses, and their dependent children. This section contains two provisions. The first states that
if a servicemember has been on active duty for more than 30 days and is domiciled or permanently stationed in a state which receives federal education assistance, that state may not charge the servicemember (or his/her spouse or dependent child) tuition for attendance at a public institution of higher education in that state at a rate that is greater than the rate charged for residents of the state.
The second provision states that
those to whom the first provision applies will continue to be charged resident tuition as long as they're continuously enrolled at a public institution of higher education in that state, even if PCS orders take them to a location outside the state.
For information about what you should do if a school doesn't understand this new law, DANTES has provided a handout.
With respect to personnel on active duty, this section of the law standardized the patchwork state-by-state arrangement that had previously existed. For Reservists not on active duty, individual state laws still apply.