If you still have a lot of OLD PCs running Windows 98, NT4 etc. IE6 is most widely accepted browser up to Windows 2000. So it may be a good idea to standardize IE6 SP1 as your web browser.
In order to download a FULL copy of IE6 SP1 so that you can install at multiple PCs within your network, simply download ie6setup.exe and then run this command.
ie6setup.exe /c:"ie6wzd.exe /d:1 /s:""#E"
.