I'm writing series of blog post about our story on how we set up a complete BizTalk infrastructure in the cloud in our BizTalk360 blog.
In these articles I explain how we set up virtual network, active directory, DNS, single server BizTalk installation and multi server BizTalk installation etc. You can read more about it here
BizTalk Testing Infrastructure in the Windows Azure cloud - Stage 1
I'll update this post with rest of the articles as and when we finish, hopefully before end of this week.