Minecraft pocket edition caves?

Srry no

Sorry, no. You can dig straight down because there's no lava underground. I usually dig 3 blocks above the first bedrock you hit for diamonds and gold. In the next update there will be caves, wolves, ocelots, endermen, stronghold (no end), better nether, bigger worlds, villages with villagers (can't trade), many more biomes, superflat worlds, lots of more flowers, and dungeons. It should be out soon. But for now you're out of luck, sry.