So, you want to learn about character encodings?
You might want to start with http://www.joelonsoftware.com/articles/Unicode.html and then start checking out the information at http://www.i18nguy.com/.
There's a very useful blog post on character encodings, their meaning and their representation, especially related to HTML and HTTP in the WHATWG blog. Check out the links mentioned in that blog post. They are very useful.
I found two books to be extremely useful when it comes to diving deeper into the subject, and especially whenh diving into Unicode workd of standards and specifications and their various implementations. The first is Unicode Demystified: A Practical Programmer's Guide to the Encoding Standard by Richard Gillam, which I reviewed a few years ago on Amazon. The second one is Unicode Explained by Jukka Korpela. If you're into Asian languages from the far east then a third book will be especially useful for you: CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing by Ken Lunde.