In Minecraft: Pocket Edition on the iPod, how do you get lava in a bucket in Survival Mode?
Sometimes lava waterfalls will spawn in your world like this:
If your world has one of these lavafalls, you can craft a bucket an collect the lava from the source block at the top of the waterfall. Then you will have some lava. If you don't have any lava in your world, then you can't get lava because there currently aren't cave systems.