I am assuming from a message you posted in another area here that you are looking to do this for a career.
You have to learn HTML and CSS. I would start there. I'd probably look at PHP and Javascript next. You can pretty much create sites with just HTML and CSS though. There are a ton of books out there. I think this is a pretty good one for beginners. I liked it anyhow.
http://www.borders.com/online/store/...sku=0470274360
I'd stay away from the 600-1000 page behemoths that are out there as you are starting out. They can feel pretty overwhelming.
If you are just starting out, I would recommend skipping Dreamweaver. Two reasons. First, it's pretty expensive. Second, I think a beginner can become too dependent on the WYSIWYG editor in Dreamweaver and not really learn the coding. There are other free or cheaper options out there. NVU, CoffeeCup, or just the basic Notepad. I mostly use Notepad myself.
As for Photoshop... That's a judgement call. If you think it's something you can pick up quickly and really like doing graphic design, go for it. Again though, it's kind of an expensive program. You might want to wait until you start making some money before spending any on a program like this. GIMP is another pretty good option, and the best thing about it is it is free.
Personally, I outsource most of my graphic design needs. I pass the cost on to the client, so it costs me nothing. Just this week I had someone design a great header for me for a site for $40.
Hope this helps.