It's just another way to pay for great content commonly and easily found across the Sony Entertainment Network.
As revealed over at the PlayStation Blog , Sony has introduced mobile billing for the SEN, which of course includes the PlayStation Store. This means you can purchase content using a mobile phone account in the US, so now you can snag games, expansions, movies and other stuff while on the go.
You can also add funds to your wallet through the PlayStation Store on PS3, or Account Management via the SEN website. While in the Add Funds portion of the menu, you can select "Use Mobile" as the payment option, enter your phone number, and respond with SMS to confirm. The wallet top-up charge will then appear on your next mobile bill, or will be debited against your pre-paid account. Yep, the whole world is goin' mobile.
Just bear in mind that this doesn't mean your mobile phone can access that content. I can almost guarantee that some people will think they can play Killzone: Shadow Fall on their iPhone or something.