Roll your rug up backwards -- in the opposite direction of the curl. Slowly roll the rug and list for creaks or cracking noises. If you hear these, stop because you could be damaging the rug. Otherwise, roll on, then unroll the rug and place it back on the ground. You should have removed much of the curl.
Weigh down your rug with furniture for a few days. A heavy object pressing down on a curly wool rug will flatten it out over time. When you remove the furniture, the rug should be flat.
Sun your rug outside. Sunlight helps rug fibers relax. After a sun treatment, lay out your rug and reverse roll it; It should lay flat.
Have a professional rug cleaner steam clean it. Like sun, steam opens up taut fibers.
Use carpet tape to secure the edges of your rug, if the corners start to flip up. Place a small piece of carpet tape under each corner to adhere your wool rug to the floor.