mcslimes.appspot.com/index.jsp -This is a slime chunk finder that find which chunks in your seed slimes are most likely to spawn. Not sure if this works on xbox though. I'm working on a
slime spawn room atm.
What you do is type in the seed, and the coordinates (central point) of home or town, and the desired distance. Less distance=less travelling. Then dig down to bed rock and open the chunk. Chunks are 16x16 areas. It helps to bring a map to see where your
x and z are.
They are very very hard to find. They take forever to spawn. Sit in the area they are supposed to spawn in and just wait. It took mine 45 minutes to show up so I just screwed around in there. Also, make the area a little bigger than you're supposed to. Slimes
only drop about 3-4 slime balls at a time, so you may have to duplicate them.