Jailbreak is simple, in that its fairly similar to Team Deathmatch for Half-Life 2. The main difference being, when you die, you respawn inside the enemy jail, that's not the end of it though!
Up in the top of your screen are two objects, firstly a radar shows you where your active team mates are, however it doesn't show you where your imprisoned team members are. This radar also shows the location of the two Jail release switches.
Also at the top of the screen are a number of player icons, shaded either red/blue or clear depending on the status of that player, and their team. Shaded players are classified as in jail, enabling you to glance up and see how both your team and the enemy team are faring.