Checking out your latest web development browser compatibility is an important thing to do, the following will help you check all the important browsers out on your own box (vmware will help you achieve all as you need macosx for multiple safari.)
http://tredosoft.com/Multiple_IE
http://tredosoft.com/IE7_standalone
http://browser.netscape.com/
http://michelf.com/projects/multi-safari/
http://www.mozilla-europe.org/en/firefox/
http://www.apple.com/safari/
http://www.google.com/chrome
http://www.oldapps.com/forum/showthread.php?t=213
http://www.thesitewizard.com/webdesign/multiplebrowsers.shtml