CoScripter (formerly Koala) is an automated testing tool for web applications.
Don't waste time reading further, just watch this awesome demo.
This neatly fits into the testing tools we've got at work: a continuous integration box, phpunit constantly running, phpcodesniffer watching for dangerous code, zend code analyzer doing the same, and our planned implementation of Selenium+PHPUnit.
Now we'll be able to tag team with Selenium and this tool.
Thank you, Mike & IBM, life just got easier.