Last night I was introduced to a very nice cross-browser tool produced by Adobe called Adobe® BrowserLab. This tool allows you to test your website in multiple browsers on multiple OS’s without the need for virtual machines, Adobe does that for you.
The way it works is to take a screenshot of your chosen URL in several different browsers and then allow you to compare each image, and see how your pages differ from one browser to another. This allows you to spot any possible bugs or errors. It does not allow you to test the interactiveness of your code though as it only provides static screen shots. Though it is still a very cool idea.