AVR microcontrollers related:
http://www.avrfreaks.net AVR microcontrollers reference site;
http://www.ullasmann.eu/ AVR "Blue Sky" Projects
http://homepage.hispeed.ch/peterfleury/ AVR starter kit, projects and sample code;
http://bray.velenje.cx/avr/ AVR project and sample code;
PONYPROGR a good programmer supporting several devices (including AVR).
La Home page di Sergio Salvitti Italian good reference site for microcontroller based projects and other ideas.