SummaryThe Choosing Colours For Your Website video is a brief discussion of the basic issues around picking colours for your site.
WalkthroughParticularly important if you already have had someone design a logo and/or marketing materials (leaflets etc) for you, then that's the first place to look for colours. If you do not have a logo already, then look at your competitors and peers in similar organisations - what colours are frequently found on their websites? Have a look at 5 or 10 sites, note what colours you like and also if you see some that don't work well together. You can also experiment with some of the colour tools listed in the resources below to create sample colour schemes.
ColorPicker.com does what it says on the tin! A really quick and simple way to generate colour schemes. Note the links in tiny text under the colour box - they generate "Complementary Colors", "Triade Colors" "Tetrade Colors" and "Analogic Colors" palettes which can be really useful.
ColorCombos.com's Combo Library contains pages of color combinations (color schemes and color palettes) for you to choose.
ColorsOnTheWeb.com (one of my favourites) is a colour matching application. They let you submit your own base colour, and automatically return matching colours for the one you selected. From their site: "It returns a set of hue, saturation and tint/shade variations of your color, as well as suggests color schemets to you, based on your color's complementary color, split complementary colors, analogous colors and other variations. The color wizard also has a randomize function that lets you generate color schemes you might not have thought of on your own."
ColourLovers.com have some more advanced tools to help you create a colour palette.
Here's a great list of 10 colour resources from Ann Smarty.