I have just released a simple Mac OS X app named “turl”, that provides a command line / shell interface to online URL shortening services (including urltea.com and tinyurl.com).
Usage is pretty simple:
There are a number of other options, including the ability to specify which URL service is used.
Source is written in Objective-C and released under an MIT License.
You can find more information, as well as download the app and source code from the turl google code project page.