It's not official, and it doesn't have a date attached, but word comes from an exclusive story on Inside Mobile Apps that a source with knowledge of the decision says Microsoft will get rid of Microsoft Points before the end of the year. The change will affect developers for Windows Phone 7, Xbox Live and Zune. (As if anyone is still developing for Zune...)
This means the frustration of trying to figure out what things cost, and having leftover Microsoft Points, will finally be a thing of the past. Which, if customer behavior is logical, should result in higher sales for Microsoft. Sure, you can do the conversion in your head, but making customers do math before they decide to purchase something is a great way to reduce their desire to buy.
According to the source, transactions will be based on the region you set in the purchasing account, and real money will be used to purchase all Windows Phone content. This means the Windows Phone marketplace will work the same way as the App Store and the Android Market, which was probably the incentive for the move.
According to Inside Mobile Apps, “Mobile developers that have publishing agreements with Microsoft are being warned to plan their upcoming downloadable content (DLC) and in-app purchases in accordance with the change. Customers with existing Microsoft Points balances will have them converted into their local currency after the switch.”
This change will simplify matters all around for Microsoft, and it will make sense for all of the various markets and stores the company is operating (Xbox Live, Windows Phone, Zune, and soon Windows 8 will have its own store).
There's no official comment from Microsoft at this point, just the usual demurrer “we do not comment on rumors or speculation.”

