Two Player Sign-In

Is there away to have two people signed in at once like on the 360? Just anoys me when im played two player and they're coming up as username(2) or whatever so whenever one of us gets a trophy it only shows up on one players trophy list no matter who unlicked it.

In some games yes (for example LittleBigPlanet), in other games no (like Bad Company 2).

Borderlands kinda lets you, but player 2 doesn't get all the trophies.