You obtain redstone from Redstone Ore. Before 0.8.0 when mined, it would just break and not drop anything.
- Compasses are made using 4 Iron Ingots and 1 redstone.
- Clocks are made using 4 Gold Ingots and 1 redstone.
- In Minecraft for PC, Xbox 360 and PS3, Redstone is used as a power source.
- In a later update more redstone functions will be added.