My question is how do I plant these seeds to ensure they germinate and grow
well? What potting medium should I use? How moist should they be kept?
What
temp should they grow in?

Check out the article by Paul Barden at:
http://www.rdrop.com/~paul/seedproduction.2004.html
He talks about the entire breeding process but if you'll scroll down toward the
bottom of the page he tells how he plants and cares for his seeds and
seedlings.
It inspired me to save a few hips this year. They are still chilling, but I
hope to get at least one seedling. Not that I want to hybridize roses, but I
think it would be fun to see what kind of rose might sprout.