There are many web sites, probably too numberous to mention. But here are a couple to get your started (in no particular order):http://www.howstuffworks.com/category.htm?cat=Comphttp://www.jegsworks.com/Lessons/lessonintro.htm
Be careful as most sites are trying to sell you a book or video or such. Also beware of sites that are directed towards children and encourage you to download ANYTHING from their site.
A good place to start with an IT career is by getting your A+ certification. For more info click HERE
The public library is a good resource. Personally, I am a reader, and carrying a book around is more convenient to be able to read, say, over lunch, or while I am laying down, because as most folks know I am basically lazy. Good luck.