I came across a popular article on Twitter today: Adobe BrowserLab. It is based on a simple and a great idea. You log in that site with Adobe ID and test your site or another ones.
Adobe BrowserLab has a basic user interface but it makes what it gotta do perfectly. It takes snapshots of the site in diffrent browsers and platforms. It supports Internet Explorer 6.0 - 7.0, Mozilla Firefox 2.0 - 3.0, Safari 3.0 - 4.0 and Windows XP & Mac OS X. I hope they will add an option for Opera which has solid fans.