You can find here links to course pages for various university courses that I taught. Some of these pages are blocked by university logins (not under my control), or deleted after a few years.
Most of my lectures are recorded (screencast + tablet + microphone). You can find the videos either on the course pages or on http://pages.di.unipi.it/fpoloni/videolezioni/ .
Also check my page on Math Olympiads for the relevant teaching material.