While not specifically aimed at children with developmental delays, this book is excellent for that purpose. Nicely laid out with lots of great inspiration. According to the author, there is a direct relationship between the physical stimulation children receive when they are babies and their ability to do well at school, supported by extensive research.
In my very unscientific observation, after one session of kindergym I have noticed my son attempting to communicate much more than any time during the past week, and being more verbal. (Kindergym at our local gymnastics club is the less strictly disciplined cousin of "Gymbaroo" which was founded by the author). Hopefully results will continue!