I\'ve been using WatiN as a testing tool for my current project. Besides the minor bugs with the Test Recorder, I\'ve been able to use it and automate a lot of my tests in c
The best Open Source automation tool I have used are Selenium IDE and Selenium Remote Control. You can then run the scripts on IE, Firefox in both Mac and Windows.
If you prefer record-play, then download the Firefox add-on Selenium IDE and then record your scripts and run them. You can very easily look at the scripts and figure out how to make minor edits.
If you want more power and flexibility of a full programming language, then consider Selenium Remote Control where I use Java and JUnit to drive the automation scripts. An easy way to started using RC is to use IDE to record your scripts, save them as RC scripts and use JUnit framework to drive your test suite.
For more information, check out:
http://selenium-ide.openqa.org/ http://selenium-rc.openqa.org/