Microsoft Corp. has today quietly added support for payments in Bitcoin for digital purchases.

The acceptance of Bitcoin means the cryptocurrency can be used to fund purchases in verticals including the XBox, Windows and Mobile stores.

In its payment and billing section, the company explains:

You can now use Bitcoin to add money to your Microsoft account. Once you add money to your Microsoft account, you can use it as a payment option to buy apps, games, and other digital content from Windows, Windows Phone, Xbox Games, Xbox Music, or Xbox Video stores.

Microsoft notes that most Bitcoin transactions should process immediately, but in the event it doesn’t, asks users to wait up to two hours to see if the transaction completes before contacting support.

However, at this stage there is no support for direct payments in Bitcoin, with the company noting “you can only use Bitcoin to add money to your Microsoft account and then purchase digital goods at select Microsoft online stores.” It adds “at this time,” suggesting that the feature may be coming in the future.

Support for Bitcoin payments is currently limited to the United States only.

It’s a huge boost for the ongoing push to bring Bitcoin into the mainstream. XBox Live alone has 48 million users, and although Windows Phone only has a small marketshare, the same can’t be said for Windows.

At the time of writing there is no official announcement from Microsoft on the move to accept Bitcoin, but if there is one later we’ll update the post.

UPDATE 9:15am December 11: Microsoft posted the news officially in a blog post here.

“For us, this is about giving people options and helping them do more on their devices and in the cloud,” Microsoft’s Eric Lockard said. “The use of digital currencies such as bitcoin, while not yet mainstream, is growing beyond the early enthusiasts. We expect this growth to continue and allowing people to use bitcoin to purchase our products and services now allows us to be at the front edge of that trend.”

The only thing new vs the earlier information is a restriction on how much BTC you can use: there is a cap on how much you can exchange per day: $1,000, and no more than $5,000 to additional Microsoft accounts that are registered in your name or by you.