Types of RPG Battle systems
There are many roleplaying games out there, and even more ways to combat in them. Below you'll find some of the common choices in a RPG. There are many more of course, especially in those free online RPG games you can download & play multiplayer with others. Practically every MMORPG has a unique battle system.
Turn Based (TBS)
These are typical RPG Battles where you have two groups fighting: your heroic team, and the enemy monsters. Each battle stops after everyone has made their moves during the round. You input new ones for everyone, and the computer controls randomly select who goes next until the round is done.
Turn based battle systems are very frustrating because you usually can't predict what will happen in terms of last hitting, and healing/reviving/item use. Many people game the system by controlling their RPG character's agility/speed scores and using it to pre-make their rounds. This means someone will usually go after the monsters, but it's well worth it for a more manageable challenge.
What is a phased battle system? It's a mishmash of turn based and active time. You set up commands like the TBS, but can cancel them at any time. Whoever hasn't moved yet can reassign their choices for that round. A popular game using a phased RPG battle system is the Wizardry series by Sir-Tech.
Active Time (ABS)
These systems are very similar to turn based, with one exception: They really are turn based. Active Time typically involves a little bar that goes up every second. When it's full, your character can make an action. Common games include Chrono Trigger and Septerra Core.
The game Final Fantasy X used a similar system, however there were no bars involved. The computer calculated everything and handled the next movements instantly. It even provided you with an ingame bar so you could properly plan them, including any time penalties from actions you took.