With a bit of research online you can find some places that offer GED programs online, but the catch is that in most cases you'll be on your own without much help. Some local colleges offer the program for free, but that depends. One other problem is they might not be legit as well. This site offers some tutorials to help prepare for the test:
Ged Online Practice Test .
I don't think you'll actually get a free program online. Most of the ones I found require that you pay for the test and course fees. And those are more expensive than the programs at the local colleges.
Mississippi GED online program GED Online High School
These are some sites I found. If you want to look for more sites, you can do a search on google or yahoo and type in "free GED programs online". Most of what I found are sites that advertise the program for free, but they are actually only offering the test preparation for free and not the actual GED test for free.