Minecraft wiki entry for Sheep, associated text: 1 wool of the corresponding color. Sheep that have not regrown their wool do not drop wool.
1–2 raw mutton (cooked mutton if killed while on fire or when in water using a sword with fire aspect). The maximum amount is increased by 1 per level of Looting, for a maximum of 1–5 with Looting III.
1–3 experience orbs if killed by a player or tamed wolf.