Great tut on how to create responsive websites. I have been doing some research on this since a lot of the Javascript gits a la 2009 don't work 100% reliably for creating responsive sites for mobile .
Morals of the article? Split your essential css for page with and content width according to screen resolutions and have it called by the browser in the head. CSS3 enables the browser to pick and translate markup according to instructions of "if the browser window is between width1 and width2 use style1.css, if the browser window is instead between width2 and width3 then use style2.css". Get it? Simple.
Also he has some great advice on handling fluid media (images) in this other article.