In the United Kingdom the Department For Children, Schools and Families has a great site called the Embedded Learning Portal. It has one hundred excellent interactive exercises on a variety of useful topics, ranging from the alphabet to using reading strategies.
The exercises use audio, text, and visuals. I have individual links to most of them scattered throughout my webpages, particularly under the Reading section on my English For Beginners page.
I thought, though, that people might find it useful to know the address of the main site.