Dingster1 - Your local MS chapter should be putting out a training schedule, my local one does. I highly recommend you do the training rides.

What kind of bike do you have? Does it fit you properly (have you had it fit at your LBS)? Can you ride 10+ miles without stopping at a minimum of 10 mph? Make sure you have watter bottles or hydropack and actually drink while you ride.

If your MS-150 ride isn't a year from now, then you should be up to doing the whole thing by then. 75 miles in one day isn't TOO bad! Really.

If you have any medical problems, make sure your Doctor is OK with the long haul biking.

Good luck!