WhatsApp now available [Mango]
We published an article covering a potential release of WhatsApp for Windows Phone within 24 hours and here we are, announcing the availability. Be sure to check out the video review of the beta for WhatsApp. If you're not familiar with the name, it's a major cross-platform IM client.
One can download WhatsApp from the Marketplace, but keep in mind the app requires Mango.