You Tube is full of good stuff on crosswind landings and rudder work, but doing it in a real J3 is much more fun.

Rudder Skills Tailwheel Training - YouTube

That guy sucked...

Better: http://www.youtube.com/watch?v=PhMhlySNXxc

When I was 14 my Dad told me, "Yeah, you could start in the 150, or the Cub....the 150 is much easier but if you start in the Cub you'll be a much better pilot." Since I'd been flying with him in his Cub since I was 8, I stuck with the Cub until I needed radios for my Private ticket. It's still one of my favorite airplanes. You never forget your first love.

You have to use the rudder all the time in a Cub, all the way to the tie downs. After about 20 hours of that, when you then transition to a nose dragger, it's very easy. You can even see where you are going when taxiing!

But going the other way (nose wheel to tail wheel) blows some people's minds.