RTLize is a rails plugin that semi-automatically allows you to use the same stylesheet file(s) to produce both left-to-right and right-to-left layouts for your markup. It does this by intelligently switching all the left/right properties and values in the stylesheets you choose to RTLize.
RTLize allows you to write your stylesheets for left-to-right (LTR) layouts and have them automatically work for right-to-left (RTL) layouts as well.