In Europe, the Prince of Persia Trilogy collection was released at retail, containing The Sands of Time, Warrior Within and The Two Thrones. In North America, however, it was a PlayStation Network release, with each title being sold separately on PSN.
…until now, that is. A GameFly listing indicates that the Prince of Persia Trilogy is being released at retail in North America as well. GameFly have the collection pegged for a March 22nd release.