I have a couple of suggestions that might come in handy that I got from a quick search:
Clean up your PS3's drive and ensure that you have at least 2G of free space.
Go into the saved data utility and delete all "corrupted file" items that you find there. These files will have the word "corrupted" in the name.
Launch the game and open the game options and turn off all four auto-save options. You will then have to play old-school creating your own manual saves but it helps a lot.
Inside of the game "Wait" for 30 game days (I did 31 just to be sure). Create a save and restart the game. This will have the game do its own cleanup of objects in the world such as arrows that you fired and missed that are still lying around, most of the bodies (some will stay), etc and thus have less objects to worry about.
The last item, number 4, had the biggest impact on my play.
Bethesda says that the problem is due to the split memory model that PS3 uses for its hardware. The issue was visible in their previous titles but it gets more pronounced the more stuff you have in the world (hence the longer you play) and there is a lot more stuff in Skyrim than the previous titles.
If that doesn't work you should consider the following?
- Is your PS3 overheating? If so you should make sure you keep it in a nice hard surfaced area (not on carpet which really attracts dust), give it some nice room to breath (you wouldn't like it if you were placed with a bunch of other equipment in a small area). Just to be safe about once a week check on your vents see if their not blocked with dust If they are grab a cleaning cloth and a low powered vacuum and clean your system.
PS. I couldn't post all sources I need at least 10 rep. Sorry