This is a great chart from Kathleen McClaskey and Barbara Bray showing some of the differences between differentiation, personalization and individualization. It's a great resource for educators who are looking for ways to do any of these three things with their students.
Personalized Learning Chart
View more documents from Barbara Bray
Tools for Differentiation - helping teachers meet the needs of all learners
Differentiation - tools, tips and resources
Differentiating with Web 2.0 Technologies
Great LiveBinder on Differentiation for High Ability Students
Differentiator - free web app to help teachers differentiate using Blooms Taxonomy