It's also known as Gram Flour - it should be available in virtually all of the larger supermarkets and will definitely be on the shelves of asian supermarkets.
Buy asian goods from asian wholesalers like paks, because I always view these products on supermarket shelves and am so shocked at the prices they charge day light robbery for most of their spices. You get a tiny packet and for that price you can get a huge packet and they give you change back.