According to Times Higher Education, in the World University Rankings for 2011-2012 the Top Ten Universities are the following:

1- California Institute of Technology. (USA)
2- Harvard University. (USA)
3. Stanford University. (USA)
4- University of Oxford. (UK)
5- Princeton University. (USA)
6- University of Cambridge. (UK)
7- Massachusetts Institute of Technology. (USA)
8- Imperial College London. (UK)
9- University of Chicago. (USA)
10- University of California Berkeley. (USA)

The first non US-UK University in the ranking is the ETH Zurich-Swiss Federal Institute of Technology Zurich (Switzerland).
The criteria that they use to create this study is very broad and it depends on factors such as teaching, research, international activity, parity in the subjects, partnership with other Universities, etc.
You can see the full list of the Best Universities in this link.