We're going to use Amazon Web Services as our hadoop cluster.  Amazon has donated credits for us to distribute to class members (thank you amazon).  You'll need to signup (including giving a credit card #) in order to establish an AWS account.  We'll pass out the credits which you can then enter into your account to cover the costs of your usage. 

Here's the process for signing up with AWS:

1.  go to http://aws.amazon.com/
2.  on the right-hand-side of the page, click on "Sign Up Now".
3.  sign into existing amazon account or register for new account.
4.  under the heading "Explore other Amazon Web Services" click on "Amazon Elastic Map Reduce"
5.  this will take you to http://aws.amazon.com/elasticmapreduce/.  on the right hand side of the page, click on
"Sign Up for Elastic Map Reduce".  
6.  At the bottom of the resulting page, enter credit card info and go through the verification process.