I found a work around to get Google Voice notifications. I'm assuming that everyone that wants to use Google Voice are using it via the browser as I am. I have created a shortcut using BetterCut for Google Voice. Next, download Google Voice Unread Count. When you install it on your home screen it will show you how many voice/text messages you have. The only problem is if you tap it, since you don't have the Google Voice app on your Xoom yet, it will fail. When I see I have missed messages, I hit my shortcut to Google Voice on my home screen. Hope that helps.