‘Teach your monster to read’ is an excellent on-line, free, early literacy games program for Windows and Mac, with an app coming soon. It is sponsored by the Usborne Foundation.
Children will learn to read letter-sounds and some letter-groups, relevant regular words and some tricky words, in a wide variety of fun activities. They include sentence work for comprehension. Adult supervisors can monitor progress and reinforce off-screen if necessary, as the children complete the whole journey.
See a review for Word or PDF file.