Do I need a visa to go to Canada from America if I have a Green Card?

I am planning to drive to Niagara Falls to see it from the Canadian side. I have heard good things about seeing it from the other side. So, I want to stay in Toronto for a day, see Niagara Falls and come back.

I have a green card, and, my wife is a citizen from US.

I have read this link, http://www.niagarafallslive.com/niagara_falls_travel_tips.htm, and this doesn't talk about person with a green card. So, could you advise if I can go to the Canadian side or give me links on this one? I am on an Indian passport.

EDIT: My experience: We went there at around 7:30 in the morning to avoid the long queue. The border security official asked us to give us our passports, I have given my green card as well with the passport, she asked the purpose of our visit and how many days we were planning to stay. The whole process took around 10 minutes, 7-8 minutes for waiting and 2-3 minutes with the official.