New forms of payment...cellphones for parking !

I was in DC the last few weeks and I was amazed to see a number of parking meters which said that you could pay by cell phone!

I think this is incredible and an insight into the future.  It is often said that the future is here with us now, it just hasn't yet taken its place center stage.  It's lurking in the corners, incubating for its big moment.

So will cell phones become a standard way of making payments? It certainly makes sense to me.  And this isn't an isolated example of how you can use your cellphone.  I've heard solicitations before to make donations via your cell phone so the system must be in place for payments via cell phone.  Maybe this is about to sweep in and become widely popular.
Of course, it might not take off.  For instance, in the past, there use to be a 1 900 business where vendors would get paid based on how long the user was online.  I'm not sure why that was never developed  further so you could just call up and key in a number (and a password) to charge it to your home phone number.
So, anybody know if cell phones are about to take off in the realm of payment? What do you think?  And would it affect online businesses like ours?