There are a few key things you should know about the Windows Azure Virtual Machine preview before you use it:
The first thing you need to do is switch from the old Windows Azure Management Portal to the new Preview Portal. Just log into the Windows Azure Management Portal and look for the Visit Preview Portal link at the bottom of the screen:
Need to switch back to the old portal? No problem just hover over the Preview area at the top of the screen and select "Take me to the previous portal".
You won't have the ability to use virtual machines until you sign up for the preview program. It's easy to sign up, just click on the New region in the lower left corner of the screen, hover over the disabled virtual machine icon, and click the preview program link. At this point you can either create a new account or sign in with an existing account if you already have a subscription. Once you have an active subscription, you'll want to click on the Account > Preview Features link where you will see the option to sign up for the Virtual Machines and Virtual Networks preview by clicking on Try It Now. Next you will be asked to choose the subscription you want to use with the preview and asked to review the Preview Terms of Use and Privacy Statement then click Confirm. If everything goes well you should eventually see this: Now you should be ready to rock! The Virtual Machines and Virtual Networks icons should be active on your portal screen as shown below:
Return to SQL Server in Windows Azure Virtual Machine Early Adoption Cook Book (en-US)
very useful.