UPDATE: As pointed out in comments, Android honcho Andy Rubin responds on the Google blog:
Here are the facts, clear and simple: While the first generation of our Android software did not support full-featured VoIP applications due to technology limitations, we have worked through those limitations in subsequent versions of Android, and developers are now able to build and upload VoIP services.
Rubin claims USA Today was made aware of this, but also says "individual operators can request that certain applications be filtered if they violate their terms of service", which basically means AT&T's no SlingPlayer, or conceivably any networks no-VoIP policy, would still affect Android, so -- okay. Let's get to it Skype and we'll see what T-Mo really thinks.
However, Rubin does dream, like all of us (likely even Apple, in public, if asked) of the day when "dumb pipes" are a reality.