Much like views. It's a good idea. Actually, considering our recent discussions about install profiles, exporting this in a format that would be compatible with install profiles/installer would be great.
I've spent some time on that: http://drupal.org/node/58153 The difficulty is faking a form submission. All the saving/updating code is right in the _submit functions, so it is hard for modules to use CCK programmatically. I've been debating factoring this out, but it is a large task. I haven't seen any love on my patch anyways, so I'm wondering if the effort is worth it, or if I should just wait for Jaza's generalized import/export API or FAPI 2.0 (which should make faking form submissions easier). In penitence for my supporting the thread hijaking, I promise to review the original patch. -Mark