Microsoft is working on a new platform for the Windows Phone.it will get new upate soon this year and when it does, it will bring a mobile payment technology to the smartphone. However, current smartphones are more than likely not compatible with the new service which means it will be available on new hardware only.
Google is doing with Android 2.3 Gingerbread where smartphones embedded with NFC, It can be used as mobile wallets. Microsoft will include the necessary code in Windows Phone so that manufacturers can add NFC to their smartphones and in turn, allow end users to make payments by waving their phone over a sensor.
The first company expected to make use of WP7(8) with NFC could be Nokia. They recently commented that all their Symbian based smartphones would include NFC which leads us on to think they might include the same with its Windows Phone smartphones due out later this year.