If you've been reading Scripting News for a while you know that I was searching for a DNS API for a few years. That problem has, as far as I'm concerned, been solved.
Amazon's Route 53 works. Like all their API's you have to learn all that it can do before you can do anything. But once you climb on top of it you can put a nice port or two on it so it's simple to do what you need to do, and then forget the complexity.
I used it for about six months without thinking about the cost, and then I looked at the breakdown a few days ago and was surprised to see that it's much more expensive than I thought it would be.
They charge a lot per domain and per name, when I thought they would be free. I don't understand why a CNAME is more than a record in a database. How much could it cost to store the fact that 12.mediahackers.org is a CNAME for pensacola.scripting.com. That's a single row in a two-column table.
But I'm going ahead assuming that either they will fix their pricing, or someone will compete, and make it easy to migrate.