Microsoft recently launched a new site called Modern.ie that seeks to simplify testing against multiple versions of Internet Explorer. There’s a code parser/validator (that cheekily flags missing IE-only HTML as warnings), and a way to get three months of free testing at BrowserStack. Far more interesting and valuable; Microsoft have finally released official IE testing virtual machines that work with VMWare and Virtual Box. This means there’s a supported, no-cost way to test IE on your Mac and Linux boxes. There are combinations of IE7 and up under Vista and newer. Some of the downloads are huge, so make sure you’re sorted for time and space.