A big struggle in game design is finding the perfect color (colour) combinations.
Lucky there are some free tools on the web available to help make your job easier.

ColorCombos.com

colourlovers.com

ColorToy 2.0, a color scheme generator
colorbe.com
Colour palette generator based on an image you upload
Colordb the colour database
4096 color wheel
Colorhunter.com 
Color scheme generator2 
colorjack.com
Colors on the Web 
colorschemer.com
Colormixers.com 
colorblender.com 
kuler.adobe.com 
colr.org
pic2color.com 
krazydad.com/colrpickr

The idea of combining images into a larger one and displaying this using CSS tricks has been around for awhile. There are a couple big benefits to doing this: First it reduces the number of HTTP requests that the browser has to make, by combining say 5 images into 1 big image, the number of [...]

Firebug integrates with Firefox to put a wealth of web development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
Just the way you like it

Firebug is always just a keystroke away, but it never gets in your way. You can open Firebug in [...]

Have you ever wanted to create a nice looking, cross-browser compliant CSS menu easily, without hardly any of knowledge of CSS? Well this site will allow you to make CSS Dropdown Menus, CSS Horizontal Menus, and CSS Vertical Menus easily — great for your game’s main menu!
CSS Menu Maker

A very nice tool is called BrowserShots and is FREE
Browsershots?
Browsershots makes screenshots of your web design in different browsers. It is a free open-source online service created by Johann C. Rocholl. When you submit your web address, it will be added to the job queue. A number of distributed computers will open your website in [...]