Europe, where Windows Phone 7 is launching first, will be safe because it is dominated by GSM, while in the US, it looks like AT&T and T-Mobile are good to go (though it's still not clear if T-Mobile will have devices at launch), but Verizon and Sprint are not. Microsoft has said before that Verizon and Sprint are key Windows Phone partners, just apparently not in 2010.
"We had to make some trade-offs," a Microsoft spokesperson told CNET. "Even Microsoft doesn't have unlimited resources. We had to prioritize doing fewer things, really, really well. For the worldwide market, the vast majority of phones are GSM phones, so we focused on GSM first and then plan to deliver an update that will have great CDMA support in the first half of 2011."
The bad news comes on the same day of the final release of the Windows Phone 7 SDK as well as demoes of official YouTube, Twitter, and NetFlix apps. In order to reach a broader market, Microsoft will need to make sure that CDMA phones start trickling out sooner rather than later in 2011 if it wants to see Windows Phone succeed quickly.