While this list is by no means exclusive or complete, many grieving parents have found the following books helpful.
Books authored by bereaved mothers
Books on Healing
Helping Kids Cope with Grief
The Invisible String (3 and older)
Am I Still a Sister? (6 and older)
Talking About Death (8 and older)
Where do Balloons Go? (4-8 years)
Help Me Say Goodbye (5-12 years)