Splitscreen - needs the patch deleted.
Lan - Not sure i've never used it myself.
Story (Campaign) - Doesn't need the patch deleted.
Online - Can't unless you use a different server using this proxy program which i read from one of silent657's posts.
For Single Player Hacks;
- Copy the CoD4 savedata onto a Memory Stick
- Put it in he PC and open it up, there should be a file called Ps3 open that.
- Go to SAVEDATA file and open that and look for BLES00148-AUTO- (thats what it says for mine).
- In there, there is a file called GPAD0_CM, open that with any Word editor and paste in the hacks.
Same appies for splitscreen but thats GPAD0_MP and from what i read looking around you need to save the cheats onto your HDD first before deleting the patch.