Yup, there will be a PSN App Store of sorts. Sony admitted as much, saying that it will focus on “snackable” games. Presumably “snackable” means short, fun games that you’d play while on the elevator, waiting in line at the bank, etc. Think Brick Breaker for BlackBerry. That game is great in a pinch.
Sony says you’ll still need a “professional” dev kit—you can’t make games with macaroni and glitter—to make these games. That said, you don’t need to a staff the size of Blizzard’s to develop the game. You and a couple of friends, armed with fiat currency, can develop the next World of Goo.