You might want to learn programming too, and Linux.
Linux: Beginners: Learn Linux (Linux Reviews)
For programming, I would recommend learning Python first, cos it's simple to learn but also powerful. I'm using Invent with Python.
I think the best way to learn about the computers themselves is to build one. Just google 'build a computer' and you should find plenty of information, or ask in the hardware section of the forums, I guess.
Hope I've helped,