iMovie
iMovie is a user-friendly application that integrates with other iLife and iHome products. Use it with iPhoto to add stills to your project, or with GarageBand to add music.
About
http://www.apple.com/ilife/imovie/
Tutorials
http://www.apple.com/ilife/tutorials/?sr=app#imovie
Resources
http://www.apple.com/support/imovie/
There are also some interesting tutorials available on YouTube
try http://www.youtube.com/watch?v=aEJjvhnA1wQ
for an introduction to the program