Cross Browser Testing
Here's some suggestions and tips to get you started with cross-browser testing.
Agree browser coverage. First things first - With so many browsers out there, it would be very time consuming (if not impossible) to test all of the them. You need to agree the scope of browser coverage with product or business owners. Suggesting to test the top four browsers based on user stats, might be an acceptable starting point. However be warned, if your stats show multiple versions of the same browser (e.g. IE6 & IE7), make sure you include these as part of your coverage.
Keep an eye out for common errors with specific browsers. The more you test, the better feel you’ll get for the flaws of different browsers. You’ll learn that the default margin on paragraph tags are different in IE than it is in other browsers. You’ll learn that min-height and min-width attributes do not function on IE6. As you come to figure out these flaws, you’ll be able to focus on these areas.
Cross-browser compatibility testing tools. There are a number of online line tools available, that allow you view how your site will look like, in every browser imaginable. However, these only allow you to test one page at a time, and include no functionality. Also, these require you to have your site live when you test. Better still - if you're lucky enough to have access to multiple test machines, then no problem. If you're not that fortunate, you can always use microsoft's 'Virtual PC' to install multiple operating systems with your required browsers.