How to install PIL on Snow Leopard

For all the unfortunate like me that came across the pain it involves to correctly install PIL to use Django ImageFields in Mac (Snow Leopard) here goes what worked for me:

MacBookPro:~ matias$ sudo -s
bash-3.2# ARCHFLAGS="-arch i386 -arch x86_64" pip install PIL

"sudo -s" is needed because ARCHFLAGS doesn't seem to get passed into sudo.