The 0x shortener now has an API available in public beta! Woo! I wonder how long it will be there before it gets abused! ;-)
Currently, it only supports the creation of short URLs, but it will extend further once I bring in the extended version of 0x, allowing user login, so that users can manage multiple short URLs and also track their short URL usage. There are a lot more things that will be available, but that will be explained as they are developed.
Details on the emerging API can be found at http://0x.lv/blog/api