Actually Skype works quite well. As soon as candidate says "my mic is not working" and "camera is broken" you know that guy with name Ashish really does not exist - it is just imaginary person made by contracting agency.

However, odesk just recently started id verification process but I still relay on simple Skype calls and actually talk to person.

If it is agency I want to talk to manager/tech lead and actual programer.