If you’re an existing Visual Studio Professional, Premium or Ultimate with MSDN subscriber, you get up to $3,500 in annual Windows Azure platform benefits at no extra charge. These benefits let you try out Windows Azure for an extended period of time at no cost.
You can activate Windows Azure here.
The Visual Studio 2010 Premium and Ultimate with MSDN Subscription benefit provides developers with an equivalent of two virtual servers that you can use to evaluate your application resource requirements. The Visual Studio Professional with MSDN Subscription benefit provides you with an equivalent of one extra small virtual server.