A mobile payment joint venture from the UK's biggest carriers, first announced over a year ago, today finally received "unconditional" clearance from European regulators. The move means that now Vodafone, Telefonica's O2 and Everything Everywhere (the JV from T-Mobile and Orange) can proceed developing a cross-carrier mobile payments platform -- not unlike the Isis initiative in the U.S. They say they will be getting the service "up and running as quickly as possible," although no launch dates or other specifics -- including a name -- have been announced. In other words, now the hard work begins.Given that one of the biggest pain points in mobile payments has been lack of interoperability between platforms, this is potentially a big step in helping such services grow: the idea is that with a bigger potential audience to serve, bigger merchants, banks, payment providers, developers and handset makers will be more likely to make the necessary investments in infrastructure themselves. read more..