Here are some links that I hope you will find useful in your projects!

Conference Presentations

A Practical Guide to Connecting Hardware to Flex
Justin McLean
WebDU - May 2009

Get Phidgety with Phidgets!
Leonard Souza
360|Flex - May 2009

Arduino / Phidgets
Martin Arviais
Montreal Flash Camp - March 2009

Articles, blogs, and such...

TutorialFlashSetup2009
Bjoern Hartmann

AIR utilizing GPS and RFID with Merapi
David Tucker

DIY Magic Mirror
alinke

Arduino + Flash + Wii Nunchuck + Servos + Webcam
yezzer

Flash / Software Resources

www.firmata.org
A generic protocol for communicating with microcontrollers from software.
Hans-Christoph Steiner

as3glue
An ActionScript library that enables communication between Flash/Flex/AIR and Arduino boards.
Bjoern Harmann

Flex C++ Bridge
Anirudh Sasikumar

Setting Up a Socket Policy File Server
Peleus Uhley
Adobe Developer Connection

Policy File Changes in Flash Player 9 and Flash Player 10
Deneb Meketa
Adobe Developer Connection

Hardware / Electronics Resources

Arduino (Open Source Microcontroller)

Parallax, Inc. (Basic Stamp Microcontroller)

Object Oriented PIC (OOPIC Microcontroller)

Basic Micro (ATOM Microcontroller)

Sparkfun Electronics (components/microcontrollers)

Adafruit Industries (components/microcontrollers)

Lynxmotion, Inc. (robotics/servo control)

Seeed Studio (components/microcontrollers)

Any Kits Electronics (components)