MobileRead - for all things ebook and ebook readers
MobileRead's Kindle Forum - for all things Kindle
Visual Kindle Guide - a tips and tricks wiki
Kindle Myths and Partial Truths - the title speaks for itself
Kindle Serial Numbers - how to figure out which Kindle model you have
MobileRead Wiki - tons of information about ereaders and ebooks.
MobileRead Wiki Kindle FAQ - Most of your questions answered."