a linux+ ebook or real book might help you out.  you need to actually use the stuff before you get good at it though.  so if you havent installed it i would start there and just start using it.

hope that helps

   I think what’s really critical for someone new to Linux is to use a distro that has a lot of community support online.  When the time comes when you want to start tweaking the OS for your security tools you will need that support and the books don’t really get into it as far as I have seen.  Fedora Core is good and there is a lot of support for it and Ubuntu is starting to have some impressive support and worth keeping an eye on.

   Google whatever distro you might be interested in and see if you are comfortable with the support you find.  If you like what you find, I would recommend going with that flavor.

  I will say that once you really learn it well, which might take a little time, you will be addicted to it and have a new found love.