Robin Good: The RWD Bookmarklet is a very useful and effective tool that allows you to test the display of any web page (even if it is only on your computer) on most smartphone and tablet display screens.
How it works: Go to this page http://responsive.victorcoulon.fr/ drag the bookmarklet onto your browser bookmarks bar and then open a new tab where you load up the web page you want to test. Then click on the bookmarklet and you are ready to go.
Try it out now: http://responsive.victorcoulon.fr/
Via Robin Good