SimpleCDN

Simple CDN is as you can guess a very simple CDN module. I wanted one that didn't need a core patch and it appeared writing it myself was the best option. It supports only Origin Pull CDN so keep that in mind.

Once installed, just set your CDN host in settings and your DOCTYPE (the HTML parser strips it from the theme; it defaults to HTML5).

If you're using Boost it'll be enabled right off the bat for cached pages.

You'll also want to enable it for non-Boost-cached pages; in order to do so simply add to the top of your template's page.tpl.php file:
if (function_exists('simplecdn_start')) simplecdn_start();

Then add to the bottom of the same file:
if (function_exists('simplecdn_start')) simplecdn_finish();

And that's it! Let me know if you'd like to see any features or report any bugs. Right now it just does what I needed it to do for my Drupal install but the sky's the limit :)