At the program I attended yesterday, the neurologist said there are two criteria for diagnosis of MS....
1 - Poser (old)
http://www.mult-sclerosis.org/Posercriteria.html
2 and the McDonald (new)
http://www.mult-sclerosis.org/DiagnosticCriteria.html
I hope this helps! I tried to find this laid out easy to read in NMSS and other reputable sites, and actually one of them sent me to this!