The English translation for converting Fuji instant film to work in an EK-8 is here: http://island.geocities.jp/sihohigari/tip/fi800.html
I bought my EK-8 just before Kodak were forced to withdraw their films so I only ever got to put one film through it. Since then the camera has stayed in its box while I waited for it to become a collector's item. Being a rangefinder and made in Germany I thought that might happen but unfortunately it hasn't. So I'm tempted to order some Fuji instant film (when funds allow!). It can be got from here: http://www.unicircuits.com/shop/ and no doubt from elsewhere.