Jayne has learned a lot with Happy and Max this summer. Head of the Class is a great free resource for teaching your kids. It has curriculum up to 8th grade. I found that for preschool, the games are very repetitive. Jayne is starting to get a little more variety now though.
The game he gets the most is a game that shows a word and he has to select the picture that goes with the word. Jayne was already familiar with the sounds of the letters (thank you Leap Frog's Alphabet Factory movie) and that gave me a chance to show him how all the letter sounds work together to make the words. He does some of the words on his own now without my help! He is good with pig, dog, cow, raincoat, and a few others. I haven't noticed that he can pick them out of text yet, but getting them in the game setting is a great start. I think there is a good chance he could be reading somewhat by this time next year.
The other game I have shown here is a math game. He counts how many pictures are shown and touches the correct number. Just to clarify, our computer has a touch screen. He is very good at doing 1-5 and is most of the way there for 6-10. We are also working on the concept of 0.
I definitely recommend using head of the class. It is free, can be used to hone some skills over the summer, and is great when there just isn't time to get things set up. Just click and go.