I applied online. The process took 1 week. I interviewed at YouGov (London, England) in Feb 2011
Interview
Entirely via email. They were mostly interested in knowing about Internet access, ability to speak English and be reasonably intelligent. I was surprised how low key the interview process was and that it was all via email. Of course, I suppose, once one attended the training and they met you, they could always decide not to offer any work.
Interview questions [1]
Question 1
If I had access to high speed Interent, was able to use Internet Explorer (required for the stats package YouGov uses) and verify one ran Windows.