The compiler it's self currently requires .NET to run on, but not for the resulting apps, which will instead run naively on any Java run-time platform, such as an Android phone or mobile handheld. Those familiar with the Oxygene dialect will be comfortable with Cooper as it shares almost the same syntax.
It is currently being worked on at their research labs, but it was shown off at the DSConf Las Vegas event live.
Get more information about Cooper and other RemObjects Software products and projects at www.remobjects.com.
Demonstration Video of Cooper Compiler (currently in development)