I found a great grill brush at BBQs Galore. It has a stainless steel scouring pad fastened to a long handle. I have stainless steel grill grates and it does the best job of cleaning I have ever seen. You can remove the pads and wash them in the dishwasher.
If my grates get real dirty, I wrap heavy duty aluminum foil around the grates and light all three burners on high for about 15 minutes. The residue on the grates turns to ash just like in a self cleaning oven.