The Automatic CSS Inliner Tool

FWIW, inline CSS functionality has long been part of the MailChimp API: http://apidocs.mailchimp.com/api/1.3/inlinecss.func.php

Useful tool.

Another one to check out is Premailer (http://premailer.dialect.ca/) which now has an API in beta and a few more options for conversion.

!confused. Using Chrome, I right-click > "View Page Source", copy, paste in the first textbox, click "Convert it" and the result seems to be identical to the input... err... what did I do wrong?

For Python people: https://github.com/peterbe/premailer

Different but related: http://htmlemailboilerplate.com/

For ruby apps there's: https://github.com/Mange/roadie

This was incredibly useful when I was designing an email template for my service. Great tool!

Now all you need is the inverse of this to fix the mass overuse of inline styles.

cool, but is there any programmatically solution for inlining CSS (for a node, coffeescript, cakefile) setup (without using any nifty templates)?

This is nifty :-)