Massive Voodoo has a nice tutorial on painting Zombicide figures.
BioSyndrome Zombie Survival Horror Game
BioSyndrome is a community created game of zombie survival horror.
Zombie Enclave Solo Board Game
Zombie Enclave is a free print-and-play solo boardgame of the Zombie apocalypse.
Painting 15mm Zombies
Given the fact that you need so many of them 15mm is the perfect scale for Zombie games. Here’s a tutorial on painting them.