I just read through this blog post and it nicely displays how the HPC Server SP1 works with Windows Azure and how you can quickly use cloud platform to scale-out you computational jobs. The details include also a great whitepaper on the topic and a video presentations of 10 minutes (worth investing if this is a scenario, you would like to implement).

This is Cloud at it’s prime: unlimited scalability as you need it for just as long as you need it! Sweet!