Location is chosen based on the availability of instructors at the schools. There is usually an IFS brief every other Wednesday and the schools are given out at the brief. Sometimes, the students will get to choose, if there are enough openings at the schools, and is usually done by seniority. Each class of IFS students will normally consist of Navy, Air Force and Coast Guard. They do brief you on the structure of each school (ground school schedules, location, time to train, etc) before you choose (or assigned as it may be). I posted some basic knowledge I have of the area schools in #57 of this thread.