The National Association for the Education of Young Children (NAEYC)
http://naeyc.org/

The National Head Start Association
 http://www.nhsa.org/

Think Small (Early childhood resources, services and education)
http://www.thinksmall.org/ 

Teacher Tom (blog)
 http://teachertomsblog.blogspot.com/

Teach Preschool (blog)
http://www.teachpreschool.org/