I can't tell much - but are you talking about the little dark specks? Could it be fleas? Both lice and fleas will cause itchiness, scratching, biting, and you probably would see tiny scabs on the skin from the scratching. You can take a flea comb to brush your cat and dump the 'debris' you find into a dish of soapy water. The soap should kill both types of parasites but will also allow you to take a closer look at what they look like.
There are topical flea treatments that also work to kill lice too. Frontline Plus and Frontline Gold both do. Any product with the pesticide Fipronil should work. As is the case with ether fleas or lice, frequently vacuuming the home, washing cat bedding/towels/blankets in hot water, along with applying flea/lice treatment to your cat should help eradicate them over time.