I’ve used the regular color key. Twice. Picked a sample from the slightly darker blue next to the guy, and then did it again for the lighter blue. It’s too easy, man! Try it.
I tried to reach you earlier but I don’t know if I did it right. I’m new to creativecow.net. I downloaded your jpeg and used two instances of Premiere pro cs3’s color key. In 3 minutes I’ve reached very promising results. You should try it.