xiaobaitu&OTHER EXPERTS:new verson of I-864EZ

Help. I have to the application by this Friday for my parents green card petition.
I do not know what difference between I-864EZ and I-864. I am the only one sponsoring my parents. I think I should fill out 864EZ, Right?
Also, the verson of either I-864EZ or I-864 on USCIS.GOV website were expired on 9/30/06.(the expiration date is on the top of the form). Where could I download valid one?
I have tried to call USCIS help line today. After 50 minutes, I still could not reach the officer.
Big THanks