We have been to Paris 6 times,and are to planning our 7th trip next year.
Is it possible to take a train out to Normandy or Saint Michel or do I need to book a tour company?

Well, yes, you can take a train to many places in Normandy, but if your idea is to do it in a day and see, e.g., the WWII sites, you can't just take the train and back - you'll have to rent a car when you get there or take a tour. Trains don't go anywhere near the landing beaches, for example.

Pretty much the same for le MSM. You can take a train to Pontorson and then a bus, or hike, but it would take all day.

You can take a long daytrip on a tourbus from Paris. Or, you can plan to spend more time in Normandy and le MSM, which I'd highly recommend.

Thanks,that's what i needed to know.

It is possible to do this as a day trip by car from Paris, although it does make a long day, and you of course cannot do full justice to the sites. Nevertheless, with my adult children, we did see the American cemetery at Colleville, Pointe du Hoc, and Mont St. Michel in a day a couple of years ago. To see what we did, you can check my phototravelogue at http://www.kodakgallery.com/I.jsp?c=...localeid=en_US

We were short on time so we went with Parisvision. We enjoyed that very much. Hope to go again and spend a few days there.