Cortex Tools
JumpStart Embedded Tools for Cortex ("V9") Help File (V1.121): HTML
JumpStart API is the best API for programming the STM32Fxx MCU (support for other vendors' MCU forthcoming). Fast, efficiently written, and programmer friendly. See here: http://imagecraft.com/documentation/jumpstart-api-for-cortex-m
AVR Tools
JumpStart C for Atmel AVR Help File: PDF HTML
"C for Everyone: The JumpStart Guide to C"
This textbook-style C tutorial reference is available for purchase in ebook or printed form here (pending) or on Amazon. While the book is part of the JumpStart MicroBox kit, this book is useful for ALL C users, not just MicroBox owners. The content of this book is Standard C with an embedded programming focus. The list of chapters is available on the online shop product description page. You can download the first 74 pages (PDF) here.
Frequently Asked Questions on C
(external site): http://c-faq.com/