Gamers using the Xbox ^[1] and Games for Windows platforms are already familiar with Microsoft Points (aka Xbox points), a virtual currency used for in-game microtransactions. An upcoming game for Windows Phone ^[2] called Birds & Beaks, developed internally by Microsoft Game Studios, now brings the in-application purchases into the Windows Phone universe–though given current trends, it could lead to a legal challenge.

Microtransactions within games are nothing new; in Birds & Beaks, as with many other games such as Angry Birds, players can use real-world currency to bypass certain limitations set within the game’s universe–unlocking levels, say, or re-upping ammunition.

Windows Phone is the sole platform for the new Microsoft game, which helps tie the hardware into the Xbox ecosystem; however, the very act of incorporating in-game transactions comes with the possibility of legal action. A number of developers incorporating in-app purchasing functionality within the iOS and Android platforms have been sued for patent infringement by Lodsys, LLC; while Microsoft has a patent agreement with Intellectual Ventures–who owned the patents in question before Lodsys–that should cover them, Google enjoys a similar agreement and yet found itself the target of legal action nonetheless.

Whether Lodsys has a rightful claim–Ars Technica refers to the company as a “patent troll”–and Redmond’s legal might aside, the new functionality may cause Microsoft some legal headaches. (Disclosure: I run the Exhaust Notes ^[3] blog on MSN Autos ^[4], which is, obviously, owned by Microsoft.)

Read more at Ars Technica ^[5].