My daughter K who also has DS, just turned 4. We have been doing flashcards with her since she was a baby & she was able to read words before age 2, simple stories by age 3.5,, & is now reading at a grade one level.
Have you tried flashing the words really quickly? I find that if I go very quickly my dd stays interested & has a great attention span. If I slow down, she loses interest very quickly. Here is a blogpost that I wrote with an explanation & videos on fast flashing:
http://downsyndromeupupupandaway.blogspot.com/2011/05/fast-flashing-method.htmlEarly reading as been very beneficial to my dd not only for reading, but also for the knowledge gained from the books she reads & most importantly speech. When she was little, it was very obvious that the words she learned through reading were much more clear than words she learned through hearing people speak.
Although we have used flashcards more than anything, I find that my dd learns well with Little Reader also. If your son likes computers, it might be a great match for him.
For anyone reading this who also has a child with special needs, make sure you check out this blog post too:
http://downsyndromeupupupandaway.blogspot.com/2011/03/exciting-announcement-from-brillkids.htmlThere is also a forum for parents of kids with special needs here. Perhaps if you posted this there you would get a few more replies.
Hope this helps
Laura