Adobe Browserlab in beta!
https://browserlab.adobe.com/index.html

when you were wrapping up developing/designing a web site and just before sending the URL or page to your clients, you've been checking the page with every single browser and OS individually to make sure it looks all right. well.. IMHO Browserlab would be a crazy sweet one-time snack for entire web-design world!!!

some keywords from marketing page
- exact preview, test and compare your web pages in multiple browsers and operating systems for web designers
- cross-browser compatibility testing, featuring multiple viewing and comparison tools, as well as customizable preferences (mmm sounds quite technical though)

enjoy :)