There are two interesting services that Sony deployed with the PS Vita: Cross Save and Cross Buy. The first allows you to pick up a save file from the PS3 when you were last playing on the Vita, or vice versa, and the second allows you to purchase a game once, but get a copy for both your PS3 and PS Vita. For those of us with both devices, these features are like the future incarnate; and for PSN games, it works fantastically.
However, when it comes to purchasing an actual PS Vita cartridge, you do not get the Cross Buy deal, even if the physical PS3 copy has this feature included. Unfortunately, I found this out the hard way.