I’ll add to this as I come across more:
The actual prep page on the NaNoWriMo website
Outlining options according to Chuck Wendig – This is a very useful post.
Some very very serious prep, something for every day of the month of October – I’ve only used this as a guideline so far.
A guide to writing awesome characters by Chuck Wendig – need to read this still but I know it’ll be useful
How to guide – outlining in Scrivener – I need to remember this website exists.
Free e-book (pdf) – Nano for the New and the Insane: A NaNoWriMo Survival Guide – I’ve only started reading this
Courtesy of Janice Hardy’s Fiction University:
Planning Your Novel’s Beginning
And her book Planning Your Novel: Ideas and Structure; A step-by-step guide to turning your idea into a novel – this book has helped me a TON
Scrivener keyboard shortcuts
Short list from “for the Dummies” that shows Mac and Windows