Do you want to test your webpages in diffrent operating Systems and diffrent browsers ? Browsershots is an option for that

Browsershots makes screenshots of your web design in different browsers. It is a free open-source online service created by Johann C. Rocholl. When you submit your web address, it will be added to the job queue. A number of distributed computers will open your website in their browser. Then they will make screenshots and upload them to the central server.

So you can test your site Here