After asking a some people involved in Christian schools and home schooling over the last few years, I believe the best program for home school and Christian schools is that published by A Beka Books
http://www.abeka.com/ and http://www.abeka.org/
The A Beka elementary reading program is based on intensive phonics instruction. The upper elementary and secondary curriculum is designed to build on a solid elementary school foundation.
Another quality program is is Bob Jones University Press http://www.bjupress.com BJU Press has a good program that provides a high level of instruction. The stated focus of the BJU Press materials is on developing critical thinking skills. Both A Beka and BJU Press materials are dependent upon the teachers. Their basic curriculum is designed for the traditional teacher directed classroom. Recently, courses have become available on dvd and hard drive. Bob Jones Bob Jones has a program on satellite called BJ HomeSat Network.
Some Christian schools use curriculum from a variety of other sources.
ACE (School of Tomorrow)
is another common option. ACE is more of a self-paced learning program. It is good for Christian schools that can't afford to spend money on teachers. It is easy to implement. One drawback is that it is that it is easier to cheat with, because students grade their own work and may retest after looking at the questions and the answers. I have heard that if you use ACE and allow retesting, it would be good to use a test different from the one in the book.
The Alpha Omega curriculum is somewhat similar to that of ACE.
Alpha Omega Publications
I have talked to a missionary that likes Sonlight
I heard that Sonlight has an emphasis on reading. It has an international outlook rather than a USA outlook on its curriculum. Make learning exciting and fun with Sonlight Curriculum's literature-based homeschool packages. We used the Sonlight Curriculum since we started homeschooling in 2000 because I love the literature approach to learning. We read real books to learn things and not just text books.
Christian Book Distributors used to have an excellent paper catalog of home school materials and a lot of books on the web site. http://www.Christianbook.com
NATHHAN: NATional cHallenged Homeschoolers Associated Network "NATHHAN is a Christian, nonprofit organization dedicated to providing encouragement for families with special needs children."
This ministry puts out a good magazine.
Cathy Duffy Home school Reviews Cathy Duffy reviews educational curriculum and parental helps available for the home school.
Cathy Duffy has one of the best web sites as far as reviewing home school materials. She has an extensive web site. However, it is not perfect, as she reviews stuff that has false doctrine.
Getting Started in Homeschooling free ebook