This is a very interesting NYT slide-show on the Tennessee Virtual Academy. This is the website of the academy, and some FAQ.
I have not heard of purely virtual schools or universities based in Central America. This is the way to go to reduce costs and improve learning. Huge economic and learning opportunities here! Why purely cyber-schools have not emerged in Central America? Is it a problem of legislation? Is there an "entrepreneurial lag" between more developed and less developed economies?