Flash is currently the nonvolatile storage of choice for microcontrollers. Fast and reprogrammable, it replaces the ROM devices of the past and enables field software upgrades that are essential for every product. Because of the importance of understanding the underlying flash, I have added it as a new chapter in my MSP430 tutorial. Granted, there are more topics and example code to be used, but the information in the tutorial is good to get a start.
As always, comments are more than welcome.