City University of New York
Brooklyn College: Endoplasmic Reticulum
A good introduction to the structure and function of this cell system.
Other
Endoplasmic Reticulum
This site provides information on the schematic and electron micrograph of endoplasmic reticulum function of both smooth and rough endoplasmic reticulum.
Cells Alive
Cells Alive!: Endoplasmic Reticulum
This Cells Alive page contains both schematic and description of endoplasmic reticulum.