Flash/Actionscript does have good gradient support, and I know that Actionscipr allows for expressing the details in code, but, what I'm thinking of is something more compact and portable. For example, you come up with a gradient, and can then easily use it in Flash, Photoshop, Illustrator, or another program.

Colors are very portable when in hex notation. This is along the same lines. Something that you can email to someone and they can just paste it into their editor and use it.

Thanks for the question!