Eh, I think it’s best you try being a web designer first. As btko has said it’s best to know these things:
HTML
XHTML
CSS
PHP (not necessarily but it’d be nice to not have to stick to html all the time and php is a pretty easy language to learn and work with)
Photoshop
Now, learning these languages just takes time, practice and patience. I think the real magic is in photoshop. I learned by just poking around and seeing what everything does etc, never used tutorials much but they come in handy if you need something specific and don’t have the time to try and figure it out.
W3Schools you should probably bookmark this site, you may be using it a lot
htmlgoodies
I think after learning all of that you can progress to learning about adobe flash, I use a lot of websites to learn flash, like:
W3Schools
kirupa.com
but I learned a ton more from friendsofed ; which means a lot because books usually never work for me.
and it’s always a good idea to find designer friends, not only because you share an interest but they’re also good for learning purposes as well. :)