10+ TESTING TOOLS FOR RESPONSIVE WEB DESIGN – Link

http://www.gonzoblog.nl/2012/03/21/10-testing-tools-for-responsive-web-design/

Interesting ones …

Use http://responsivepx.com/ for all browsers

or

http://www.jamus.co.uk/demos/rwd-demonstrations/

or

use resize option with web developer plug-in for FF / Chrome

or resolution test chrome plug-in

https://chrome.google.com/webstore/detail/resolution-test/idhfcdbheobinplaamokffboaccidbal?hl=en-US