Hi and welcome to LQ
The whole understanding Linux is a bit of a bit question. Over to the right you will see links to our book review section and at the top a link to our Tutotial section. They may be a good start point.
I would also suggest going to the RUTE website and downloading a copy of the book. Also check out www.tldp.org
- lots and lots of documentation there.
Basically, we are good with specific questions, but the huge open ended ones like this are a bit of a tall order.
The reading will also help with your dial up/AOL question. Our Search function (top of the page again) will also be of help. Oh, and don't forget www.google.com/linux