Starfall.com is the best website I have found for students who are learning to read, and early readers, and it is FREE! Yes, free. I still can't believe that with all the work the creator put into it that they do not charge for it...but I will not look a gift horse in the mouth.
I have been using this website in my classroom for the past seven years and have seen marvelous results. The best thing about it is how engrossed my students are in the content!
I could tell you all about the content on the pages; however, I feel that checking it out for yourself is much more effective.