The goal of ETL Unit is to facilitate and standardize test driven design and continuous integration around common tools such as Informatica, SQLServer, MySQL, etc. ETL Unit is modular and encourages extension to as many platforms as the industry uses.
ETL Unit is not another generalized testing framework. While it does not limit what can be tested, it's strength is in testing unrelated tools which are difficult by nature to test.
There is a use case on this WIKI which shows off a lot of the parts of the framework with an accompanying webcast which helps demonstrate the ideas. Hopefully this will help to show the potential.
Here are some tutorial videos to help address certain problems and a Getting Started guide.
There is also a Change Log for release versions.
You can also browse ETLUnit Documentation Home.