I've found that simply reading the documentation[1] was enough to get started. The package reference[2] was pretty easy to understand after going through it. I would also make sure you're running the current RC and using the information at http://weekly.golang.org/ as it's the most up to date and has some substantial differences compared to the stuff at http://www.golang.org/

[1]http://weekly.golang.org/doc/

[2]http://weekly.golang.org/pkg/