Styling checkboxes, radio buttons and dropdowns

Short answer: You can't do it nicely and consistently.

The answer you might want to hear, depending on your situation: Use jQuery or something similar, which will give you plenty of plugins to choose from.

These two are some of the better ones, as it will let you style just about all of the different controls.

see this 2 links for jQuery Plugins for Styling Checkbox & Radio Buttons:

http://line25.com/articles/jquery-plugins-for-styling-checkbox-radio-buttons

http://www.queness.com/post/204/25-jquery-plugins-that-enhance-and-beautify-html-form-elements