What OTHER documents do i need to travel to Canada besides a Green Card, and my 'world' passport???

do i need any other papers? should i visit the Canadian embassy?

As long as you have a valid passport you should be fine - depending on what country your passport is from. American, British, European, Australian passports are definitely fine. If you are a permanent resident of the USA you should bring your greencard.

Citizens of some countries do require a visa - so you should check with the Candian Border Service Agency to see if you need a visa. Follow this link and click on your country and it will tell you exactly what you need:

http://207.219.111.92/requirements/steps4.aspx