This might be old news, but since when do you need a passport to get into Canada?

This is not Canadian law, it is US law. After Jan.14, you will need a passport and visa to enter the US from anywhere even if you are a US citizen (because you have to prove that).
Obviously Canada can not let you in if you do not have a US passport, because you would not be able to re-enter your country and would become a refugee.
As for accepting draft dodgers, the situation has changed since the 60's. Immigration was wide open then. Now it is more controlled. Canada was not involved in the Vietnam war, but now Canada is in southern Afghanistan.
It would be hypocritical for Canada to lobby our NATO partners to send more troops to Afghanistan while welcoming draft dodgers from the US.

The rule which they are gradually implementing has to do with needing a passport to ENTER the USA. In February (Isaac says January, he would know better :-)you will need a passport to ENTER the US by airplane or cruise ship.

However you (you: a U.S. citizen) will not need a passport to enter (REenter) the US by automobile or bus (or train most likely) for another year.

U.S. citizens with proof of citizenship (driver's license and birth certificate) can enter Canada and re-enter the U.S. for another year, by land.

Anyway right now today citizens of the U.S. and citizens of Canada can travel to each other's countries freely, by land, with identification and proof of citizenship, it doesn't have to be a passport. The rules haven't changed yet and will change gradually, air and ship traffic first, then later car and land traffic.

Thanks Mercury, I stand corrected.
Still, I have had friends turned back at airports for not having a passport, before these rules went into effect. Their driver's license wasn't good enough because it doesn't prove citizenship.
The best thing is to just get a passport.

don't worry - you'll still be able to freely come & go from Mexico

No, you are right, a driver's license isn't enough, you need proof of citizenship, a properly notarized copy of a birth certificate is what is needed in addition to a passport.

I cross the border a lot as I am dating a Canadian fellow. I just use my passport. I don't drive and they really do not like a state-issued ID that says "this is not a driver's license". They assume you lost your license because of a DWI or something. I don't take kindly to being singled out for not driving so I am happy to avoid the issue and use the passport instead. Best to not get upset about anything while dealing with customs officials. Must keep a cool head at all times! No matter what.

That's right Mercury, both Canadian and US customs officials ask the stupidest questions. I think that it's part of their interrogation technique.
One time I had to spend several minutes explaining the concept of credit cards, ATM, and payroll deposits to a US customs oficer who wanted to know how I planned to get to Florida with only $50 in my pocket.
My favourite was the Canadian officer on the Alberta/Montana border who looked at my Northwest Territories license plate that said "Explore Canada's Arctic" and asked me "Are you from Alaska?"

A US officer on the New York border came unglued on me once because I listed my occupation as "prospector". He claimed I was trying to be smart with him. I had to give him an entire overview of the mineral exploration business before he let me through. After that I just said "mining technician".

You don't need the passport until 2008. I live in Buffalo, right across the border from Niagara Falls, Canada. Big article in the Buffalo News about this misconception hurting tourism.

Is it true that you can't enter Canada from the US if you've EVER had a DUI in the US?

Yea, if youve had a DUI you cannot enter canada. its considered a Felony.

Don't you all think this is fuc ing bulsit. We have people from all over the world here and coming from Mexico etc. and our govt hassles it's citizens like this. Let's just put up great wall of China on Canadian and Mexican border, concertina wire and guards with German shepherds partrolling.

That'st he police state of America right now. We are all guilty of anything and everything until we prove ourselves innocent. The terrorists hate our freedoms so much, we have to do that to citizens. The 5000 illegals that enter America an hour are exempt from all this.