
Pages must work in current versions of IE, Firefox, Opera, and Safari and one previous version. The sites must look acceptable in each of these browsers, they do not need to look identical, that may prove to be an imposible task.
http://www.browsrcamp.com - where you can enter a URL and an Apple Safari screen shot is generated, however to get the other mac browsers, you have to pay a fee.
http://browsershots.org this site has every browser you could ever want to simulate, but it take FOREVER. The average wait time is 20-30 minutes.
After simulating the browsers you may want to download the software to fully experience the browser experience. While a simulator can take a screen shot, however you cannot use it to simulate drop down menus or a hover effect. To test that functionality you need to have someone on the team who has the software installed on their computer.
Browser Extras
Designing for the iphone a videocast from CSS-tricks
http://css-tricks.com/video-screencasts/38-basics-tips-on-designing-for-the-iphone/