As you may have heard, Bethesda is having quite a bit of trouble getting their expansion packs to function acceptably on the PS3, and it has caused numerous delays. While Dawnguard released for PC and Xbox 360 back in June, it is still missing in action on PS3.
Similarly the latest pack, Hearthfire, is available on 360, but there's no release date in sight on PS3 (and PC for that matter.) However, according to Sony, they haven't abandoned the idea of getting the DLC on PS3 eventually, and they are currently working on resolving the issues with Sony's PS3 developer support teams.
"We work with all of our partners to try and solve their problems," Sony vice president Adam Boyes told Kotaku. "We have a big, broad dev support team that works closely with Bethesda--and with all of our partners--to work with them to solve that any sort of issues they have along the way. Of course, I always want everything to work always for everyone. I can't promise any kind of resolution or timeline but can say that everyone involved is trying their best to get this stuff working."
Last month, Bethesda reportedly said that there was a possibility that the PS3 may never get Skyrim DLC, but apparently they (and Sony) aren't willing to give up without a fight.