I am absolutely not a graphic designer. Usually I start with a dominant colour that I like (for example the default orange header here) and I'll plug it into a colour-match system like http://colorblender.com/
Another resource I've used to good success is http://kuler.adobe.com (requires flash) which lets people (some of whom are quite a lot more competent than I at this) create and share colour themes.
Finally, a neat tool that I saw make the rounds recently is http://www.gpeters.com/color/color-schemes.php which lets you search on a word and uses Yahoo!'s image search to come up with some colour suggestions. That is not a theme place, but it's a fun way to perhaps stumble across a colour you like to use with tools like those above.
Another resource I've used to good success is http://kuler.adobe.com (requires flash) which lets people (some of whom are quite a lot more competent than I at this) create and share colour themes.
Finally, a neat tool that I saw make the rounds recently is http://www.gpeters.com/color/color-schemes.php which lets you search on a word and uses Yahoo!'s image search to come up with some colour suggestions. That is not a theme place, but it's a fun way to perhaps stumble across a colour you like to use with tools like those above.