I checked www.zinio.com about this, and all I can find is a page that says it is coming soon to the Android market, and that we should check with our mobile carriers for details. I am not sure why the carrier should matter when it comes to apps.
So, will the Zinio magazine app will be available for the Motorola Xoom at some point? Having that app would turn the Xoom into the perfect tablet. Right now it is close to perfect, but not quite there yet.