Job openings are posted around 5am & are taken down usually by 9am, when they've received the number of applicants whose resumes they can evaluate that day. When applying, if you don't answer the multiple-choice questions the way they want, you won't be considered for the position. A recruiter there actually told me to lie, just to get past the automated system's filter.
After you find an open listing, apply in time & answer the questions correctly, a recruiter will call you (within about 4-7 days) for a brief phone interview with extremely basic questions. After you pass that stage, you'll be emailed, asking that you go to the company's regional People Department for a formal interview. The People Department can be 100s of miles from the airport where you'd be working, & you (the applicant) are responsible for any costs or travel incurred because of the interview.
Next, you'll meet with a member of the People Department for a face-to-face interview. It's critical to be punctual, appear extremely upbeat, eager, & able to handle any challenges Southwest's customers could throw at you. It helps to remember the 3 values that Southwest prides themselves on: servant's heart, warrior spirit, & fun-loving attitude.
The recruiter didn't give any indication of whether or not he would recommend I be hired. I found out later that since the background check can take about 3 weeks, they don't tell you anything until they make sure you don't have a criminal past. Roughly 3 weeks after the interview, I got a call saying I was hired. They usually hire several people at once, so that they can all train together. They'll give you one or two dates to start on. I think the first one was about a week away. I said I needed to give my other job 2 weeks notice, so I took the 2nd start date that he mentioned. I was given the impression that if neither of the dates they offered worked for me, that they would retract the job offer.
After I was hired, I was told that statistically, it's easier to get accepted to Harvard University than it is to get hired by Southwest (because sooooo many people apply & don't make it).