"We're excited and eager to bring Fallout 3 DLC to PSN. Unfortunately, the content is going to be releasing later than originally expected. Our DLC expands on the original game tremendously -- each DLC offering 4-6 hours of additional content -- and is no trivial undertaking...
...So when can you expect Fallout 3 DLC? We are knee deep in testing at the moment, and we're hoping to have the first DLC out by the end of September." -Ashley Cheng
Fallout 3's first DLC pack made available for PS3 was originally supposed to be but has now been changed to . Operation Anchorage will be released on PSN "shortly thereafter" the release of Broken Steel. Three other DLC packs, , , and will be released sometime after these two expansions are available on PS3.
Read the from Bethesda for more details on the delay.