I have two Pokémon game cartridges on the same Dream World account. Is it possible to trade or share items between them using the Dream World?
Maybe I'm a little too late, but just in case: You can "add yourself" as a friend in the Dream World. That is, make a Dream Pal request from one game account to the other. That way you can easily access your other game's Dream World home, and swap items using the Share Shelf. I did it by trading between my games and then searching on the Dream Pal map for my Game Pals (there you can see the people with whom you've battled/traded). You can trade with yourself using the GTS in order to do that, if you only have one console.