I was asked to find some resources on BizTalk and Windows Azure Integration so after my research, I found the following article by Paolo Salvatori from Microsoft, about integrating BizTalk Server application with Windows Azure Service Bus Queues. The article is very detailed and required a good long sitting to consume it however at the end the reading is absolute wroth of your time.
Read: How to integrate a BizTalk Server application with Service Bus Queues and Topics
This article shows how to integrate a BizTalk Server 2010 application with Windows Azure Service Bus Queues, Topics, and Subscriptions to exchange messages with external systems in a reliable, flexible, and scalable manner. Queues and topics, introduced in the September 2011 Windows Azure AppFabric SDK, are the foundation of a new cloud-based messaging and integration infrastructure that provides reliable message queuing and durable publish/subscribe messaging capabilities to both cloud and on-premises applications based on Microsoft and non-Microsoft technologies. .NET applications can use the new messaging functionality from either a brand-new managed API (Microsoft.ServiceBus.Messaging) or via WCF thanks to a new binding (NetMessagingBinding), and any Microsoft or non-Microsoft applications can use a REST style API to access these features.