What exactly do you mean by "coding?" Are you actually teaching them a programming language? If so, what?
I am still working on pulling a few things together. They played with Logo, had some fun, but grew tired of it. I was gonna go Java, some decent stuff out there for teaching kids.
Just ran across this a while ago, still researching - http://www.kidsprogramminglanguage.com/ - figured I would play with it over a brief christmas break. my break is over and I didn't get to it...
Right now I am teaching some basic concepts without a language - looping, decision making, very basic stuff.