A group of Columbia Law students created Keep Your Copyrights, a site specifically to explain the basics of copyright to creators. Although, on the surface, the whole concept (keeping your copyright) seems like it might be skewed to the more proprietary view of copyright, the explanations are nicely balanced. For example:
[I]f you do know what uses you want to permit, and want to allow those uses for free without people having to ask you, that’s fine, too. If you want people to use your work for free and don’t want to create a do-it-yourself list of uses, the Creative Commons licenses are one shorthand way of describing what uses you want to permit and forbid. If you don’t want people to use your work for free, however, ready-made online licenses may not be a good idea.