Its a very good question and Eurogamer have created a video that tries to answer it. I quite like some of the reactions from the first party devs to this and its very interesting how they are trying to show that the PSVita is much more than your typical handheld and more like a console. [...]
The PS Vita is only a couple months from launching here on the States/UK and Europe. February 15th 2012 if you get the early edition bundle (this is just in America). The bundle includes a 3G vita a 4GB memory stick a limited edition carrying case and the game Little Deviants.