Yes of course- Nubians were still used, of course primarily by the Muslims, as archers during the crusades. Even into almost modern times their ability and reputation as archers saw them recruited.
Another great example of the African prowess with bow would be the Mali empire. The cream of the Mali army were the knights and other cavalry, but most of the army was made up of supporting infantry. Of these 3/4 were archers.
As I understand it, the African bow in the Mali army was not always the most powerful due to the poorness of natural woods, but this was somewhat compensated by the use of deadly poisons on the arrows. Since only 1/4 of the infantry had to be spearmen, it can be inferred that the archer was extremely deadly.
The Nubian bow, which I personally presume had to be some kind of composite bow, was immensely powerful, as evidenced by a story recorded by Herodotus. When the Persians wished to invade his land, and he handed the Persian emissary his bow with the challenge that even one Persian could now string it. By most traditions, none could, and by a few, only Emperor Cambyses' brother could (leading to his death by jealousy).
In Africa, javelins probably overpassed bows in importance as range weapons. This is specially true in the northern part of the country.
However, bows were used by sahelian people, from Nubia to Mali. As cachibatches commented, Nubian bow was powerful, while Malian bow was of lesser power and arrow points needed to be poisoned to increase effectiveness. People of Guinean forest used bows too, as they were used against Europeans.