I have found a really useful website that can tell you both the PANTONE and the RAL colour numbers of any shade. It also automatically shows you a list of complimentary colours for each shade. It also tells you its RGB and hue percentage, and probably much more. A website that may come in handy in the future.

http://colorschemedesigner.com/

I also found a website primarily directed at graphic designers and interior decorators. It generates colour schemes, along with all the information you need to get it yourself, and if you find that too difficult then there's also an option to export the colour schemes straight into Photoshop, Illustrator or as a swatch.

http://www.colorjack.com/

Ikea colour wheel

I have come across Ikeas relatively new catalogue. The Ikea Color Spectrum was designed by Jessica Reynolds. It presents the entire furniture catalog arranged on a color wheel, which makes it both simple and beautiful to look at. This original idea allows for easy colour matching across the spectrum.