I have a 6 year old gelding that I just found out is actually a standardbred. He has a slow walk, 3 different sppeds of  a racking gait and then a lope type of gait. I am new to the "gaited" horse and was wondering if anyone can give me any information about this breed. He has been trained to gait naturally, but it was before I purchased him, so he is out of practice. I only use him for pleasure/trail riding and currently use a western trail saddle, do I need to change to a gaited saddle? If so, what is the biggest difference.

I have Walking Horses, so until an SB owner comes in, here's a good link to introduce you to the very aristocratic Standardbred

http://www.thegaitedhorse.com/standardbred.htm

Gaited horses ride in any type of saddle.  The important thing with gaited horses is to be sure the saddle is of good fit for it (and you:), and that the shoulders are not being pinched.  Gaited horses have a lot more shoulder movement than walk/trot breeds.

They also have a lot of hind quarter movement.

If you lunge your fella, he will need a wider circle than a walk/trot horse to allow for his large shoulder and hip movements.

Hope to see pictures of your fella and to hear of your progress together