I own a 3 year old paint/ pinto gelding. He is very willing and i would love to teach him dressage. I have no idea where to begin! Any help or comments would be greatly appreiciated!

Dressage is only the name given to a series of movements performed in a pattern to demonstrate the training and education of the horse, if your horse can walk , trot and canter in a forward balanced and correct way then he is already doing dressage!

Dressage is only a method of training, any horse can do it, however the WAY they do it will determine if they are to become a champion or not.

Get yourself some lessons with a good coach and go from there.

Even though I don't do Dressage as my main sport, dressage can come into whatever you are doing.

I would recommend getting a qualified trainer and let him/her teach you so that way you won't be starting any bad habits by trying to do it yourself. 

Agreed, if you have access to a trainer, go for it.  But the heart of dressage is getting your horse moving smoothly in all three gaits and having rhythm, balance, and straightness at all times (or in my case, in occasional moments!  LOL).  These are things you can practice on your own, as they are things that come only a few strides at a time.  Helping your baby build muscle in his hindquarters and topline and learning to go in a consistent rhythm is a great start.  Then you just take that rhythm, balance, and straightness and apply it to circles and diagonals and changes of direction and oops, you just made a dressage test.

Here are some books that might be helpful to get started until you find that perfect trainer:

http://search.barnesandnoble.com/booksearch/results.asp?WRD=dressage&z=y&r=1

I particularly like the 101 Dressage Exercises.  And previous posters are absolutely correct - basic dressage is the foundation for ALL disciplines - I call it flat work.  It's only as you progress through the ranks that the fancier movements become the symphony.