Jan Wildeboer noted in his blog that:

Microsoft: Absolutely NO (GPLv3-or-compat-licensed) Free Software for Windows Phone and Xbox Apps.

The issue hinges on the definition of Excluded License which include, but are not limited to GPLv3 Licenses. My initial impression was that other Open Source licenses might not fall under this Excluded License category. However, the and any equivalents to the foregoing squashed that notion (I should note that I am not an attorney and this is merely my personal interpretation).

This is a bit of an irony since Microsoft provides a Bing Open Source SDK for iPhone developers:

Microsoft Bing Open Source SDK Available for iPhone Developers: Will It Get Used? Why? (ThinkMobile, Aug. 28, 2009)