Can anyone point me in the direction of some good documentation that deals with customizing CMF? I'd like to build several sites using CMF (and/or Plone) but need to change the look and feel. Any help is greatly appreciated.

Perhaps the Plone Book on plone.org will help. The short story on changing the look of a CMF site is simple: if you want to make a slight modification to an existing skin, use the cusomizing features of the skins tool. You can change any of the skin files TTW (or on disk.) If you want to make a big change, make your own skin directories (on disk or TTW) and just make the site, using the existing skins as a guide as to what can (and probably should) be included. --jcc