Getting a player that enters a cuboid

Is there a method for getting a player object when the player enters a certain area? If not, how would I do it? I'm assuming there's a better way than constantly getting the list of online players and checking to see if someone's in that area.
--- merged: Feb 14, 2011 7:19 PM ---
After scouring the javadocs, I guess I have to make a class that extends playerlistener, then use onPlayerMove and then use .getTo and parse out the location. I guess this works, but it's called every time any player moves, so is there still a better way?