Jumbo Fun with the Alphabet can be purchased from Handsandhearts.com.
For my kindergartener, I'm using Phonics Pathways to teach her reading. I also have a book called the Jumbo Fun with the Alphabet. While the latter sounds pretty hokey, it really is a very nice book and I've gotten a lot of use from it. It has several activities for each letter of the alphabet including snacks and crafts. In the file folder book, I've just taken various pages from those two books and let her paste them in. For cut and paste activities, I attach velcro instead of having her glue them and then she can do that activity over and over. It takes her a few days to complete a folder and she thinks it is the best fun. Also, she gets to reinforce learning those letters without the dull moments of sitting in front of flash cards.