Many talk about IA when they really mean navigational design, and to a great extent I'm one of them. I've spent the past three(ish) years talking to groups around the university about how and why the website needs to change, in anticipation of us implementing a new content management system that will give me the opportunity to see change through.
I've always used the term information architecture, and while I'm covering topics such as search and taxonomy, the main focus is always on navigation design. It's challenging because I am responsible for very little content; I'm just trying to see through the best consistently presented solutions to many many university websites' content structures.
As we soon enter the critical phase of launching these many many sites in quick succession as we move them over from the current CMS to the new one, I'm about to find out if my planning and groundwork has anticipated everything the new navigational design needs to accommodate.
The Difference Between Information Architecture (IA) and Navigation - article by Jennifer Cardello for useit.com
Framing the Practice of Information Architecture - article by Nathaniel Davies for uxmatters.com