I want to register some .eu domains but
 

it says invalid country (USA). Is it Europe only? If so, can Europeans sell them to non Europeans after registration?

~Ray

EU only? yes.
Can Europeans sell them to non Europeans after registration? No.

www.euregistar.com :

" To register a .eu domain name, you should meet one of the following elegibility criteria:

* Undertakings having their registered office, central administration or principal place of business within the European Community.
* Organisations established within the European Community without prejudice to the application of national law.
* Natural persons resident within the European Community."