Advice: get there at least 1:30 to 2 hours early; though check-in at the gate does not begin until one hour before flight time, the line begins to stack up well in advance of this time, so if you get there at the recommended one-hour before departure check-in time, you'll probably only get a middle boarding card (ie, 30-60).
Southwest boards in four distinct groups, and eschews the traditional seat assignment/boarding pass system. When you check in, you receive a colored boarding card with a number on it. The color corresponds to your flight, and the number is in one of four ranges: 1-30,21-60, 61-90, and 91 and above. Each of these comprises one boarding group. The first boarding group (1-30) goes on first, then the second, then the third, and so on. There are three seperate lines for people in the first three boarding groups to queue up at many SWA gates, and you can wait in line with the other 29 people in your group. Occassionally, some dolt who doesn't understand the boarding procedure gets in the wrong line and gums up the works, but the procedure works just fine, otherwise.
SWA's service is excellent, and their employees are extremely friendly, if not a bit hokey...but it's the hokey humor that they use which makes the trip fun. Corny jokes and sly comments are what keeps both employee and customer morale up.
Look for the crazy plane-shaped visors that many SWA employees wear nowdays as an example of this.
Service inflight is honey-roasted peanuts or pretzels and soda. Often, they'll even give you the whole can. Flight attendants make corny jokes before,during,and after the flight, and the pilots sometimes join in, too. Sometimes, the pilot will talk to you, and others, he'll stay silent for most of the trip. It all depends, just as on most carriers.
I've never once had a problem with Southwest in several trips with them, and have always found them to be an excellent value for the money!
Hope you have a nice trip!