WHAT DATE EXACTLY OF CHRISTMAS CELEBRATION?

Wednesday, December 12, 2012.
I read SHNEWS.COM. I read news about Christmas at Philipine that had started on September every year. I  know from  this news that in Indonesia, evidently at Manado almost just as it. Why I just as shock? I'm Flores' people. In our tradition, Christmas  become on fourth month of December because almost during 1 month celebrate Advent period. Than, after it Christmas. This is Catholic tradition.
How with the other Christian Church? On Metro TV I see advertising about announcement of Christmas celebration on Tiberias - Jakarta. It  was done on Saturday, December 8, 2012  at Gelora Bung Karno, Jakarta. Wow.........? It is so difference with Catholic tradition that just celebrate it on December  25. Which date that right? Plese find it on your reflection.