Preschool children are very curious about the world around them. If parents answer their questions and help them find answers to those questions in books, their children will be far ahead of their public school counterparts. I have some preschool guides and a great list of picture books that parents can read to their children listed on my website at Preschool Ideas.
Many states don't require students to even report to school until they are 6. That means that parents are free to homeschool preschool AND kindergarten without even needing to worry about telling the school. Most administrators won't tell you that, but it's true.
You don't have to be an expert or have a college degree to walk with your children and teach them what they need to know. This can all be done in a low-stress, high-results method outlined on my site and in my guides.
Have fun with those kiddos and give them lots of hugs because they grow up WAY too fast!