I have a pair of the fleece ear warmers that slip over the helmet straps. They are triangular and have velcros across the top opening to keep them in place. I find they are great for cool but not cold weather riding. When it does get cold, I compliment them with a windstopper skull cap that completely covers my ears. I'm not sure who makes them, but I'm sure I've seen them recenlty in my LBS. They are kind of an obscure item, but they work.