As always, libsurl is under active development, and contributions of all forms are welcome.
Contributing to libsurl
There is no TODO list per se, but it is libsurl's goal to support every major URL shortening service available. If you are a developer and can take the time, and know of a service which libsurl does not support, please feel free to write an engine for that service. The engine can then be submitted as a patch either via a branch in launchpad (see the launchpad documentation) or as an email to the libsurl maintainer. If you are not a developer, you can file a bug mentioning and linking to the service.
Bored developers can also always go look at the bugs database and submit patches for ones they view as trivial, via a bazaar branch in launchpad.
Libsurl supports two methods of extension - templates and processor functions. Any extension to libsurl, once written, can either be built into the library or simply applied by a client program at runtime.