In addition to the comprehensive
documentation on skins, we've just published 16 free video
tutorials describing how you can create your own skins for the
starter kits coming in Umbraco
Juno.
This outlines in detail how to get started and it describes all
the different aspects (like the default dependency types and task
types that can be used to setup customization options, how you can
execute task during installation of your skin, how you can enable
module injection on your custom skin, how you need to package up
your skin, …).
Go check them out.
Before the release of Umbraco Juno, we'll make it possisble to submit skins via Our Umbraco.