Hilton HHonors members can choose to earn either double points or double miles for all Hilton stays at participating properties worldwide through June 30, 2012. You must register for the promotion at www.HHonors.com/Double and select to earn either double points or miles and once you’ve made your choice, you can’t change your selection.
If you select double miles, be sure to change your Double Dip earning preference to Points and Variable Miles or Points and Fixed Miles and select an airline partner if you aren’t already earning miles for stays.
If you select double points, you don’t have to change your earning preference but you can maximize your bonus points by earning Points and Points. All stays at eligible rates completed between April 1 and June 30, 2012 are eligible to earn the bonus, even if you booked the stay prior to April 1. There is no limit to the number of bonus points or miles members can earn and the bonus can be earned on up to two rooms per stay. There is a rather lengthy list of properties that are not participating in this promotion at http://www.insideflyer.com/link/?6266 – Be sure to check out the list before making reservations and expecting to earn the bonus.