, if you have an Intel-based Mac, you can run Microsoft Internet Explorer on it.
A forum member of Ars Technica has managed to get a working, albeit buggy, version of Internet Explorer 6 to run under OS X via WINE. Using a script designed to easily install IE 6 on a Linux machine alongside a version of WINE designed for OS X he managed to get the ubiquitous web browser to run. We don't need to tell you how happy web developers will be to find that they can test their sites on the Mac without booting into Windows, or even owning a copy of Windows for that matter.
