If you missed the The Business of Windows Azure: What you should know about Windows Azure Platform pricing and SLAs PDC session,it gives a clear vision of Azure business model.

Some important highlights about this session :

• There will be three purchasing models :
  • Pay as you go
  • Subscription licensing are plans for payment predictability
  • Volume licensing :Available through centralized purchasing experience and will have volume discounts
  • Additionally,there are some offers that you can join with important benefits (some of them requires an MSDN subscription)
• The TCO Analyzer Tool helps you to  quickly determine the value of using Windows Azure.
• SLAs : One of the key parts of the Windows Azure Platform is the Service Level Agreements,you can check the terms of the agreement in the link.

I would recommend you to attend this session,it’s really worthless!