Include this meta tag in the <head>.
<meta name="viewport" content="width=device-width, initial-scale=1.0">
Internet Explorer 8 or older doesn’t support media query. You can use media-queries.js or respond.js to add media query support in IE.
<!--[if lt IE 9]>
<script src="http://css3-mediaqueries-js.googlecode.com/svn/trunk/css3-mediaqueries.js"></script>
<![endif]-->
I think this two links will help you.
- http://cssmatter.com/blog/ie7-and-ie8-support-for-css3-media-query/
- http://webdesignerwall.com/tutorials/responsive-design-in-3-steps/comment-page-2
Update
css3-mediaqueries-js is moved on github