I think one of the things that can be difficult to get to grips with is the directory structure. Like "where is every thing?" and "where should I put this?".

Here is a starter: http://www.tuxfiles.org/linuxhelp/linuxdir.html

The distribution you use will have variations and its own way of doing things.

If you really want to get to grips with Linux, install it on your desktop. Ubuntu should make it relatively painless, but you'll end up in the command line whatever version you use.

And that is where you want to be after all...