Marriage Greencard Question

I am in New York City area now and gonna get married with US citizen soon. We plan submit application right after marriage. Here some questions I need help with

1. I check the INS website and it seems New York Office is processing I485 on June2001 now. Does it mean I need wait 3 years to get my conditional greencard if I submit my I485 now? Am I understanding right? Or at that time, I get unconditional greencard? And What is the stamp on passport?

2. According to the website of INS, people can apply for naturalization after 3 years of marriage with citizens? Is that 3 years after get conditional greencard or 3 years after marriage?

Thanks very much!