Episodic content is exclusive to GTAIV for 360.
That means actual episodes (extentions maybe of the MQ, ect) are going to be available.
However, I am near 100% certain at a minimum they'll have some extra content. I believe the wording is key. Its signalling that (IMO) the 360 is probably going to have the better content, but I am near sure that GTAIV PS3 will have something for it - but probably less.
Why? I think Rockstar is going to push the bigger (and more costly) content on the system destined to make more cash. Simple economics.
Back from the dead, I'm afraid.