The movie is called "The Silver Stallion" in the US and "The Silver Brumby" in Australia where it was originally filmed. It's just stunning. Half the movie or more is spent out with the herd of brumbies. I still don't know how they managed to get these horses to do everything that they did completely at liberty. The music is gorgeous during the rest of the movie as well.
The final kicker? Russel Crowe is "The Man" who pursues the silver stallion relentlessly throughout the movie. I believe it must have been one of his first films. He's pretty good in it... and certainly quite handsome. ::)
Here's the song, plus a taste of what the movie itself holds in store. If you like it, I can email you an mp3 of the song.
I will admit that the movie is a teeny tiny bit sappy from time to time, and if you're looking for things to nitpick (like the fact that the horses are all obviously domestic or that a mare occasionally plays the role of a "stallion") then you'll find them. But my advice is to watch it like you were a seven year old girl again that just couldn't get enough of horses and their beauty.