While you can find Southwest Air Fares on southwest.com or southwestairlines.com you can also find them on WhatsCheaper.com where you can compare them to fares from other airlines.
Southwest operates over 500 Boeing 737 aircraft. They serve nearly 70 cities. Southwest is likely the most successful low cost carrier. Unlike most hub and spoke airlines, Southwest is a point to point carrier operating more than 3,000 flights per day.