Microsoft is now selling Azure as a cloud-based HPC solution for scientists, too. Sounds pretty good:
Microsoft today unveiled its behind-the-scenes work on porting a popular suite of supercomputing software tools to its Azure cloud platform. It's work that culminated in an a test job that the company says would have cost an estimated $3 million if it had used traditional on-premises hardware, but it got the job done for a little more than $18,000 using a hybrid approach. The teams ran a large chain protein sequence through BLAST, a software tool set designed to churn through databases, which in this case were all known DNA base pairs in the human genome.
BLAST is a computationally expensive search algorithm, especially when running against such a huge set of data. In fact, these searches "have proven too taxing for the search and analysis system maintained by the National Center for Biotechnology Information (NCBI), which makes protein databases available."
Having used the NCBI's BLAST tools before, I can tell you that they are certainly backed up. The ability for scientists on any scale to tap into a huge network of computational power to alleviate that problem is awesome. Microsoft gets props for making science cheaper, faster, and easier.
[Sources]
http://news.cnet.com/8301-10805_3-20022738-75.html?tag=mncol
http://bits.blogs.nytimes.com/2010/11/17/microsoft-gives-the-cloud-to-scientists/