I applied online. The process took 6 months. I interviewed at FAA (Aurora, IL) in Mar 2010
Interview
All applicants had to be Certified Air Traffic Controllers to be eligible to bid for this job. The job announcement was posted online at USAJobs.gov. The application had to be submitted online, and involved uploading a resume and answering four essay questions (aka KSa's) - each with a 4000 character limit. The best qualified candidates were interviewed (your choice of in-person or via telephone) by a panel of four. The questions all pertained to managing people and government employment policies, not technical air traffic situations.
Interview questions [1]
Question 1
What do you know about the annual strategic plan for the facility you are bidding?