The Embedded Linux Home Page: http://linux-embedded.com/
Linux Memory Technology Device Home Page: http://www.linux-mtd.infradead.org/
M-Systems Home Page: http://www.m-sys.com/
Circuit Cellar Home Page: http://www.circellar.com
Linux Device Drivers, by Allessandro Rubini, O'Reilly (1998). Though over two years old, this book is an excellent introduction to writing Linux hardware drivers.
``Embedded RT-Linux, Part 2: Working with Flash'', by Ingo Cyliax, Circuit Cellar, December 1998. This is one of the first articles I read on the subject of Linux and Flash memory. It provides an overview from the hardware perspective.