Various PSP blogs and message-boards are carrying the news that you can share a single cartridge for multiplayer play by letting the game load in a PSP, removing the cart, and passing it on.
…[Y]ou do need to let the 1st PSP completely load into the game, and then only can you remove the game to place it into the second unit. Now on the second unit go to ad-hoc mode and find the server that is already started. Enter the game, which means load it, and now you can remove the disc if you wish to add a third or fourth unit into the game.
