There are many good resources online. This is just one of many:
http://ripatients.org/tips/strainguide/ Just Google "medical marijuana for ms" and you will find a lot of good resources.

However, MMJ is almost as individual as are MS patients. I prefer sativas, the headier strains, because a) I don't want to be stuck on the couch all day and b) they often give me relief via the nice high that distracts me from the pain/spasms/etc. Unless I am unable to get to sleep, I rarely reach for an indica first.