I went to Robert Half because a friend had used their IT service to get a land a job. I wasn't interested in the IT, my interest resided in the legal field. I was a recent college graduate with limited experience as a paralegal. The first week was slow as far as offers, the 2nd week it picked up.
The process is simple:
You apply online, by uploading your resume.
They call you in for an interview.
The interview is pretty standard: Tell me about yourself? What are your interest? What are your strengths and weaknesses?
After the interview they assess your interview with you things you can work on and so forth.
That pretty much it.
I landed a job within 2-3 weeks.