Starfalls
This site is great for practicing phonetic rules. There are a variety of games and controlled texts. There are also some really great movies that teach rules and concepts.
PBS Kids
This is a great site for early childhood learning. There are familiar characters the children can relate to. I really like the songs and videos from Between the Lions.
BBC
There are a lot of fun poems teaching more difficult vowel rules. There are also a variety of fun games or beginning readers. However, the british accent can get in the way.
Reading is Fundamentals
Lots of information on this site. However, it is a bit hard to navigate.