There's lots of good stuff out there for Advent, Proost are one of my favourites, and they now have an Advent Calendar too, courtesy of Si Smith. Here's a few of their bits and bobs:
Advent Calendar - 25 images by Si Smith, plus a meditation for each day, available electronically.
Nativity Figures - these are really good, download the images then print them out on white card. Had great fun making these a couple of years ago in a Christmas service.
9 lessons and carols animations - by Jon Birch (ASBO Jesus), flash animations to show during the readings of the traditional 9 Christmas readings. Youtube preview here.
Silent night movie, also by Jon Birch.
nine - 9 artistic pieces to go with the 9 lessons and carols.
All available for download.
Or use the 'Advent' tab below to browse resources from other places.