Soak very cold water for 10-15 minutes, then soak hot as long as you like.

I cut down my soreness by 2/3rds when I do this.

The cold water flushes out the lactic acid and helps the blood carry away the damaged cells by constricting the veins. The hot water then causes expansion, bringing in more blood to help the repair process. (This is also why icing helps remove swelling from injuries, it's like a mini-icing for your whole body).