Not much to say here other than the guys at Designwoop.com put together this GREAT source for online (paid and free) testing tools for responsive web design. Check it out:
http://designwoop.com/2012/04/tools-for-testing-responsive-web-design/
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Essential Responsive Web Design Testing Tools
A list of Responsive Web Design testing tools you need to try out and bookmark/fave/tweet right NOW!