Lexington Christian Academy is the largest, and best, Christian school in Lexington. It is large enough to offer most sports programs (although they are the only school in town without a lacrosse team). The facility is fairly new and houses middle and high school. I'm sure they have a website but I don't know it right off.
Lexington schools are considered Fayette County district. There are several factors in deciding on a public high school.
www.fcps.net has a listing with a link to each high school. Dunbar and Henry Clay are considered the best two overall. There are several magnet programs within the high schools. Dunbar has a Math, Science, Technology program. Henry Clay has The Liberal Arts Academy magnet. It is for identified gifted kids. These two have admissions criteria. Tates Creek will have an International Baccalaureate program starting this fall. Lafayette has a Pre-engineering program. Each of these have link from the schools site that describes the program and admissions criteria. Dunbar and HC's magnet programs list their average ACT and SAT scores as well as which colleges offered scholarships to their students. Tates Creeks website is not as informational.
Bryan Station has a brand new facility but the scores are usually well below the other schools. It houses a Spanish immersion magnet but kids have to start in it at kindergarten.
If your child is in a magnet you do not have to live within that school district. If they are not you have to live within the district. From fcps.net you can search by street name to see which district it is in. Most of the online real estate listings will list which school dsitrict the house is in.
www.lbar.com(I (broken link) think this is correct) lists houses that are on the multiple listing.
There are a number of other private schools. Sayre is an excellent prep school. Lexington Catholic is also a very good school.
There are several other web sites I would look at to get an even bigger picture:
www.lexchamber.com/doc_lib/BluegrassRanking.pdf
www.visitlex.org (broken link)