Is it possible to make Facebook's comments widget a fluid width? Their documentation shows a width field for the fb:comments xfbml or iframe which is specified as:
So maybe it's not possible...
I found a solution using css. Inspiration came from this article http://css-tricks.com/2708-override-inline-styles-with-css/
.fb-comments, .fb-comments iframe[style] {width: 100% !important;}