Playstation Network Store

So, now that Sony is shifting to digital download for their games (and I would assume phasing out UMDs) I guess I need to learn how to use the Playstation Store. So, I was wondering, how do you pay for games from the PS store? Are there prepaid cards (like Wii points), or do they bill your credit card, or do they send a bill to your house? I have never seen prepaid cards but there should be a way to pay for games with cash.

Thanks