If you plan to show the horse cutting then its really not worth it. Unless you get a professional you will only be spending money on entry fees. There are sooo many little things professionals know that someone who isnt professional will not realize.
If you want to do it for fun I say just get out there and move some cows.
Yeah, unless you are already pretty experienced in cutting, it would be very difficult to try and train a horse to become a cutter without a trainers help. There are a lot of little details that are greatly fixed by having a trainer watch you ride and point out. I'm sure he would still be fun to push cows with :)