Unfortunately there are not a lot of practical books about tech and ECE out there. Even if there were- they would be out dated almost by the time they were printed! Technology is rapidly changing. I am in process of developing an e-book about using tech with young children but it won't be ready until late fall. Even then, my hope would be to be able to update it as tech changes.
Here is a book recommended by another reader and published by NAEYC: http://www.naeyc.org/store/Spotlight-on-Young-Children-and-Technology
There are however, a lot of resources on the web regarding using technology with young children. Here are some to peruse:
NAEYC is of course the first place I go for ECE advice and this position statement should be thouroughly read by anyone using technology with the 0-8 age group.
An accompanying document to the NAEYC position statement this doc gives practical ideas for use of tech with children at each age level.
This site ECE Tech, is new to me... explore it and let me know what you think.
This article by NAEYC speaks to tech in primary classrooms but still has gems for the preschool teacher as well as ideas for activities.
Have the kids work with partners the majority of the time. My rule is the kid on the right (in front of the mouse) makes the decisions- which links to click and what to type. Set a timer and switch every 5-10 minutes. This helps with social skills, reduces frustrations and gives them someone immediately there when they need help. In the beginning partner a tech savvy kid with a new to tech kid.