Oracle released its AMIs for the cloud. The important piece of news in this is that customers can use their oracle licenses on the cloud, with the following conversion:

"When licensing Oracle programs with Standard Edition One or Standard Edition in the product name, the pricing is based on the size of the EC2 instances.  EC2 instances with 4 or less virtual cores are counted as 1 socket, which is considered equivalent to a processor license. For EC2 instances with more than 4 virtual cores, every 4 virtual cores used (rounded up to the closest multiple of 4) equate to a licensing requirement of 1 socket." 

Here is the oracle website page for the cloud - link