Start off with basic Html code. You can find several tutorials all 100% free all over the internet, then once youve mastered that, start learning a little Java script.
Once youve gotten good, purchase your owwn domain and hosting, and sownload and install apache, MySQL and a php editor, and start learning those. Free tutorials are also available online.
You can also learn some css, which will help you create very awesome looking menus, or you can find a free code generator on line.
To design good looking graphics for your site, you should also learn how to use Adobe Photoshop, or GIMP which is basically the free open source version of photoshop.
Once you've mastered those the only thing left to learn really is flash, and ssl security stuff.
With that you should have enough knowledge to build very powerful and interactive sites.
If you want to go further like become a virtual warrior, fighting off hackers and defending your website, then you will need to start using a command line OS like any flavour of linux. Fedora and Ubuntu are very good options for beginners. You should also learn a programming language like C++.
If you want to be a pro, the easiest thing to do is go to colleage and do a degree in software engineering or computer science. They will teach you everything you need o to know and when you grafuate in 4 years you can get a good job earning lots of money.
Believe me, unless your very very good and have connections, you need a degree to get a decent job as a web developer.