One of the big remaining mysteries around Microsoft's new mobile platform, Windows Phone, is when, or whether, the software giant will make its Zune Pass music subscription service available outside the United States. Microsoft had previously tied Zune Pass to its US-based Zune players, negating the need for an international launch of the service. But with the Zune platform heading to Windows Phone and to the Xbox 360 this fall, both of which are available around the world, many have wondered about the company's Zune Pass plans.

Turns out, Zune Pass is almost certainly going international. The enthusiast website WMPowerUser has published a screenshot detailing the service's UK pricing, the second time in recent weeks that a Zune Pass leak for the UK market has been revealed. According to the shot, Zune Pass will cost 8.99 pounds per month or 26.97 pounds for three months. This compares to US pricing of $14.99 per month, or $44.97 for three months.

Zune Pass is one of several advantages that Microsoft's Zune platform has over Apple's iTunes-based ecosystem. It provides unlimited access to the several million songs Microsoft offers via the Zune Marketplace via the PC software, the Zune HD, the web, or, in the near future, Windows Phones and the Xbox 360. Subscribers can stream the content on the fly or can download songs and sync them with devices as long as their subscription is active. Additionally, subscribers get 10 free song downloads to keep each month, in DRM-free MP3 format.

Microsoft won't yet comment on its Zune Pass plans. "Zune Pass is currently only available in the US," a Microsoft representative admitted. "\\[But\\] we are testing Zune features and functionality in various markets. As previously confirmed, Zune PC software will be the synchronization client for Windows Phone 7 but we're not sharing details around market availability at this time."

Apple purchased the music cloud service Lala.com last year, triggering rumors that it, too, was going to finally offer a music subscription service. No such service has materialized, though Apple did just launch an iTunes-based music social networking service called Ping that mimics the Zune Social service Microsoft launched back in 2007. So it's possible that an Apple competitor to Zune Pass could still emerge in the future as well.