I know most of you might be familiar with HTML coding. But I would anyway give some information about HTML/CSS/Javascript and how to start
Books
====
HTML/XHTML - The complete reference is a good one to start with.
But frankly for HTML any online tutorial is more than enough.
www.devguru.com has a good reference section.
For CSS - any Eric Myers books are good, though some of them are way advanced.
Learn CSS in 10 Minutes is again a very good book.
For those who can invest some money, go buy the Lynda.com tutorials or you might find them on a p2p.
Javascript - The complete reference is a good book.
Tools
====
You need a plain browser and a notepad to start and nothing else. But I suggest beginners to stick with some simple HTML editor like Frontpage and dont use the WYSIWYG editors. EditPad is a good one again.
Online References
===========
devguru.com has a good reference
There are many other references which you can Google for.