The 9/11 Memorial organization in New York has released a Windows Phone 7 app, the 9/11 Memorial Guide, to help visitors to the memorial find information on victims and via oral history listen to remembrances of those who were lost, spoken by family and friends.
The app helps users explore the site, and includes maps, photos and biographies of those who dies so tragically there.
The app also provides information on the Memorial cobblestone sponsorship campaign which allows individuals and organizations to sponsor cobblestones on the Memorial. Given that the only names allowed on the Memorial at those of the victims, the names only exist online. Without the contribution of these companies and individuals the memorial could not exist in its current form.
The app is of course free and can be found in Marketplace here.