Guy Kawasaki is hosting a really good article describing how to run handling interviewing for a tech company. The best point I tihnk it makes is find out how your best interviewers are and have them interview everyone. “Best” in this case is “measured by the retention rate and the eventual performance of the people we hired”.
I cannot stress this enough:
A curious thing about our interviews: We were VERY hard on the candidates (particularly the Tech interviews), but instead of resenting it, the candidates uniformly were impressed and wanted to work for us. They knew that if they joined, they’d be joining a top-notch R&D group.
Signum sine tinnitu–by Guy Kawasaki: The Art of Recruiting, Part II