Is there a cheat to get more magicka in oblivion for the ps3

Yes there is for all platforms (I think all the good glitches work on all platforms like cloning yourself, duplication of items and infinite level up)

This will teach you how to infinite level up on oblivion.

1) Make a save file that is ready to level up.
2) Go to a bed and press on it, slide the rest bar to around 10 hours so u have more time if you make a mistake.
3) once 1 hour or more has passed (in game time) pause the game and load your save file you want to level up. (this is why I said 10 hours in case you miss the first few hours)
4) You will get the level up screen on your loaded save file.
5) To get more magicka just select "intelligence" as one of your attributes.
6) save your game and repeat from step 2 (because you can keep using your ready to level up character)

Another way is to make an enchanted item with "fortify magicka" on it and use the "permanent enchantment" glitch using it.