The first step n solving an indoor mold problem is stopping the source of moisture. Next is to remove the mold growth. The most common remedies for small occurrences of mold are sunlight, ventilation, non-porous building materials, and household cleansers.
Make sure the room is well ventilated before you begin. If the mold covers a small surface are it isn't too hard to clean it with detergent and water. Allow the space to dry, and then apply a solution of ½ cup bleach per gallon of water to help kill the remaining spores. There are products available that are specifically designed for mold. The Centers for Disease Control offers many tips for mold cleanup. Remember that the mold will very likely return unless you eliminate the underlying problems that caused it.
Significant mold growth may require a professional cleanup service and removal of affected building materials. A conservative strategy is to discard any building materials saturated by the water intrusion or having visible mold growth.