Nikon School Online, which provides video tutorials by professional photographers, is free for the entire month of April.

The class topics include landscape photography, macro photography, photographing kids and pets, portraiture, and music videos, as well as focused tutorials for Nikon equipment.

Classes range from 15 minutes to over an hour, and there are ten in total, so you could learn a lot over the course of April.

Source: Nikon Free Online Photography Classes | Apartment Therapy