Starfall is a great website for beginning readers. It includes activities at various levels, from alphabet recognition to reading comprehension questions. http://www.starfall.com
ABC Teach offers some fun activites for students. Please note that some are free, and some are for members only. http://www.abcteach.com
Mighty Book offers great games, activities, and books that help teach reading skills. http://www.mightybooks.com
National Geographic for Kids http://www.nationalgeographic.com/kids/
NC Wise Owl http://www.ncwiseowl.org/