That tutorial is as good as you'll get I think. You can edit shaders in notepad but it's slow and you can only use commands you know whereas with a specially written program the commands are all infront of you as check boxes.
Also you can find a set of tools with ShaderEd2 in it here.
ShaderEd2 is the best shader editor for JA as it has least bugs and you just tick boxes as to what things you want the shader to do. Also you can preview your shader in ShaderEd2, whereas in Q3ASE there are so many bugs you can't really preview the shaders.
As for tutorials the tutorial I sent you to was for Quake 3 which uses a game engine that is almost the same as the JA one (JA engine is based on Q3 engine) and shaders for both are exactly the same.