IE7 Standalone:
http://weblogs.asp.net/jgalloway/arc...a-3_2900_.aspx
Personally, I installed IE7 as normal (so it's my main, default IE) and downloaded the standalone version of IE6 from here:
http://browsers.evolt.org/?/ie/32bit/standalone
As for safari, aside from buying a Mac, you're out of luck.