I really want to have a basic understanding of what certain capacitors, and diodes, and all those do. What are some good books or sites that will help me understand these concepts? Thanks!
When I was learning the basics I went along to my local library and had a look through the electronics section. Thankfully there was (still is) a lot there!
I found there wasn't a single book where I understood the big picture straight away, but between them everything started to fall into place bit by bit. Although a little on the large side, Malvino's 'Electronic Principals' explained a lot. If your library hasn't got it they might order it for you, but chances are what they have got will be enough to get you started.
An awful lot of what you want to know is available on the net but it can be tiresome finding it all, and unless you print it all off it's not as easy to read on the bus/train as a book.