I am thinking of designing a site using the Flexible box model but I understand that anything less than IE10 will not support it. Is that true? If so, are there hacks or prefixes that I can load for the earlier IE browsers to get it working? Thanks.
If you are talking about [flexbox then there are no robust polyfills for it and really you should avoid using it for any professional use for the time being. I believe even ie10 [URL="http://zomigi.com/blog/flexbox-syntax-for-ie-10/"]uses the wrong syntax](http://html5please.com/#flexbox).
ie10 uses the older syntax. IIRC, Modernizr has detection for it. It'd be easy enough to use that to cover browsers that don't support flexbox.