It is hard to find a rhythmic gymnastics hoop tutorial online, let alone one by a gold medalist, but Alina Kabaeva, Russian olympic gold medalist in rhythmic gymnastics (and, weirdly, Vladimir Putin’s mistress) has a hoop tutorial on YouTube. It’s in Russian and is translated into Japanese but you can pick up a lot anyway. The hoop tutorial starts at about the 5 minute mark.
http://www.youtube.com/watch?v=8wz62J6RTN4
She has other tutorials on YouTube also, including one for a contact juggling ball.
http://www.youtube.com/watch?v=0zUyW0sNTD0&feature=related
This is Alina in action in 2007. Breathtaking!
http://www.youtube.com/watch?v=gvDU4rmzmhg
She also has quite a few tutorials on ballet, stretching, ribbons and other rhythmic gymnastics training techniques.
Enjoy!