According to a GameStop advertisement pre-ordering a copy of Diablo 3 on the PlayStation 3 will net you an Infernal Helm in-game.
The promotional material was spotted by DiabloFans, who also mentioned that the Infernal Helm provides additional experience bonus to players. However, a level-cap or numbers weren’t mentioned. We don’t know for how long that helm will do you good until finally being worn out as you level up and find better items.
Chances are that the helm probably scales with you as you level up
Additionally pre-ordering the game specifically from GameStop will also get you a double-sided Diablo 3 poster. One side features Diablo himself, while the other depicts a battle scene.
Diablo 3 was announced for the PlayStation 3 and 4 earlier this year in February. Blizzard announced that the console versions of the game will feature an updated UI and will also support offline play.