It's later.ATB
The ATB is on the upper right hand corner. I will call this the ATB list. It shows when everyone will be having thier turn. For example, Yuna, Lulu, and Tida are fighting a monster The list on the right hand side shows Yuna with her ATB bar, then lulu under her with her ATB, and Tida with his ATB. Then there is a monster icon (a B) and his ATB. There is a white line along the left side of the ATB list that shows who in line is in the cuurent rounbd. The order for the next round is also shown under that with a black line to the left. Pressing the R2 button will show the turn order beyond the next two rounds. Pretty cool. If there is a character below the one who is "up" who also has ATB you can press the triangle key to use them, but you can't do as much. (longer spells are disabled, you don't have the time to cast them). After that character's attack is done, the next in line pops up and the ATB list ir re-ordered.
During summons, the characters no longer battle. All of them leave and you just control the summoned monster. The ATB list is now not used and is gone. No idea how long the summon battles last.
Along the top there is a semi-trasperent "help" bar that tells you what does what. You can turn it off using "select"
I feel better about the battle system now.
-halkun