After attending a "Pre-Screen" interview on my college's campus, I began to go online to post my resume to different job postings. I'm still not clear on the purpose of these pre-screen interviews, but my guess is that they just want to make sure you can communicate clearly before asking you to interview with a manager for a particular position.
First off, if you interview for a position in the Engineering Leadership Development Program (ELDP), Lockheed Martin will treat you VERY well! They put us up in a nice resort, three meals for both days with a very good dinner on both, tour of their plant, etc. They truly make you feel special during this interview process.
There was a group of about 50 candidates at this event selected from about 5 different disciplines - Electrical, Mechanical, Systems, Software, and something else. They split us up into two groups - one to interview the first day and the other to interview on the second day. Your "off" day is spent taking a tour of their facilities.
You are interviewed by a panel that consists of managers and fresh recruits. The questions that they ask are not hard at all, and it almost seemed as though they were mostly trying to get to know your personality. There were some stingers - "Tell us about a time when you failed and how you dealt with the consequences." No one likes to remember those times, but it lets them know how you will react in these situations.
Overall, a very good experience. No offer as of yet, but not counting it out.