This is really something. In the past, you needed to take 3 quick shots yourself and then use specialized software to create high dynamic range photos. We're talking about the domain of for-reals professional photographers use this stuff to create the incredibly beautiful images you might see in galleries.
Now, this clearly is not going to make everyone gallery-ready, but HDR can really take a tough situation for a picture and make it damn reasonable, if not somewhat excellent.
I'm looking forward to seeing if it actually works.
http://www.appleinsider.com/articles/10/09/02/first_look_taking_hdr_photos_with_apples_ios_4_1.html