I have a box-shadow around the layout container of my site to separate it out from the background. However, this works only in Firefox, chrome, etc and not IE.

You can see the site here: http://www.firesteveaddazio.com

Try viewing it in IE and in Firefox and you'll immediately see the difference. How can I get this working in IE?

Wait till IE supports box-shadow.

Seriously, there are lots of CSS things that IE does not support. You can search in google for work arounds and then try to implement. IE is the bane of all web developers