Articles:

• Different Strokes for Little Folks: Carol Ann Tomlinson on "Differentiated Instruction" (Educaton World article)
• Reconcilable Differences? Standards-Based Teaching and Differentiation: Carol Ann Tomlinson (Ed. Leadership article)
• CAST (A center that focuses on Universal Design) has a great article summarizing the concept of differentiated instruction, and a great bibliography

• Wilmette, Illinois has a very thorough program for long term staff development in Differentiated Instruction.
• ...and a superb resource page

• ON-Line course in Differentiated Instruction from ASCD