Testing a site in different browsers and on different operating systems is essential if you want to produce a professional looking site that can reach the widest possible audience.

Here are a couple of sites that can help.

browsers.evolt.org is an archive of old browser versions for windows, mac, linux and other operating systems. You can download virtually every browser that has ever existed and test your sites with them. Handily, the old versions of Internet Explorer can be installed as ’stand alone’ applications so they don’t interfere with your current IE version.

If you don’t have access to browsers on different operating systems, Browsershots.org is an excellent free service that generates screenshots of a webpage in different browsers on Linux, Windows and Mac. Of course, this only shows that a page is displaying correctly, it doesn’t show anything dynamic like hover effects etc, but it’s better than nothing.