Conduct a literature search for various funding sources related to your Project. Write a summary of your findings.
(I know your research is on ADHD, but many of the sites below can be used for other topics as well.)
Below is a list of several funding services that I think would be willing to fund research on ADHD in preschool children. I am not sure of your current status (undergrad, graduate, phD, teacher wanting to write a grant, etc.) so some may not apply to you currently.
National Science Foundation - Research in Disabilities Education
Klingenstein Third Generation Foundation
(Click on "Research Grants")
Finding Funds for Educational Research