The micropayment market is far too lucrative for the payment processors for anything to get done.
There can only be bickering and fighting with nothing resolved other than 50 trillion micropayment systems in the end and a frustrated consumer. The closest thing out there is PayPal, and it will remain that way until the big guys move in for the kill.
At the moment it looks like Google is positioning itself to try it, but they've been screwing so many things up so badly lately that it's hard to say if they'll be able to get it right. They screwed the pooch with Google Video but did so well with GMail. What's up with that? If their Google Base (or whatever the heck it's called) turns out as bad as Google Video they'll just end up losing the market to someone like Microsoft.
But you never know. A good open standard would help, but would still leave open the question of "who processes the transactions" and "who holds the money"? Those are the questions that will kill micropayments no matter what.