If I might offer my two cents here.

First things first: Find yourself a good text editor. You don't need anything fancy; I personally use TextPad (www.textpad.com). It's small, fast, and easily customizable. Whatever you do, don't rely on a WYSIWYG editor, such as Dreamweaver. It may seem easier at first, but once you really learn how to code, you'll realize that it produces horrible code, and you'll spend more time correcting it's mistakes than actually developing.

If you don't know HTML yet, you will probably find it easier to learn the table structures first. This is especially true if you ever plan on working in a group environment, or with clients. (Some clients have needs that can't be met by true standards-based development.) After that, move onto learning CSS positioning. The concepts are not that hard, but learning how to work around the various bugs that each browser has can be downright frustrating.

My advice: pick up a book on HTML / XHTML and learn it front to back. There are a lot of web sites that offer tutorials on HTML, but most of these sites will teach you bad habits, and outdated methods. (By the way, one of my favorite books out there is Jeffery Zeldman's "Designing With Web Standards". (You can find it on Amazon.)

Also, visit sites like MezzoBlue, A List Apart, Digital-Web, Zeldman, Inman, etc. Read as much as you can, and try to learn something new everytime you sit down.

Lastly, don't get discouraged. This is a learning process, and will take time. Keep plugging away, and you'll get there.