Article by Jeff Atwood on Pair programming and code reviews with conclusion:

In the end, I don’t think it’s a matter of picking one over the other so much as ensuring you have more than one pair of eyes looking at the code you’ve written, however you choose to do it. When your code is reviewed by another human being – whether that person is sitting right next to you, or thousands of miles away – you will produce better software. That I can guarantee.

Pair Programming vs. Code Reviews