1) Expression Web SuperPreview : EW SP for Internet Explorer is a stand-alone visual debugging tool that makes it faster and easier to migrate your sites from Internet Explorer 6 to Internet Explorer 7 or 8.
Download Link :
File Size : 18.3 MB [ Freeware ]
* IE 8 should be installed in your machine to see the difference
* Script is not working in this tool, if you need script you have to install Expression Web 3 Trial.
2) Expression Web 3 Trial - Supports [ MOZILLA, FIREFOX, OPERA, SAFARI ]
File Size : 123 MB [ Free 60 day trial ] Currently it says trial as this tool is in beta but Microsoft will soon make it Free