Hi guano,
Seems like everybody can be a web designer these days! It's really not that hard to wip up something generic, but when it comes to being a little more creative and making things looks clean and professional, it does depend highly on not only your creative abilities but on knowledge of your graphics programs. But graphics design can be learnt! You don't always have to have a knack for it, but of course it really helps if you do.
Some people have suggested Macromedia Fireworks, Paint Shop Pro, and Photoshop. I use Photoshop, Image Ready and Illustrator. But Macromedia really does all 3 programs in one for the web. One of the biggest things is to know how to replicate things that you see on the net that you like and alter them to fit what you have in mind. So knowing the programs well really helps when being creative.
Some of my rules I follow, keep things simple, don't use more than 3 fonts on your page, no more than 6 colours (and in the same general tone), don't use blinks and horns to attract people, remember to have white space, use sans serif fonts for titles since they are easier to read, make buttons only when necessary, and keep them a small size (don't get too fancy with their shapes either), Put text into sections like you would when writing a report, and think user navigation instead of always just what looks "cool" or "pretty". Think logically, and create graphics as a means to communicate something, not for the sake of having it there for no reason whatsoever.
And probably the most important one is "look at a lot of sites and try to replicate and add to them!" Believe it or not, nothing is original on the web... everything is copied from one place or another (I'm talking about ideas of course). It's just that they are altered in different ways, incorporated and such, to make different designs. Just don't go copying and pasting code and graphics (copyrights do exist!).
There's plenty of design how-to sites on the net. So do a search on google, I'm sure you'll be able to find plenty of resources!
Good luck and hope that kind of helps!
-Vanessa