The way I understand it, starting today, crossing the border into Canada is not a problem. Its getting back in, although Channel 5 said last night that even without the passport or enhanced drivers license, you could still do it, it just might take a while.
For more information, click on the following Burlington Free Press Article:
http://www.burlingtonfreepress.com/article/20090601/NEWS02/906010319 (http://www.burlingtonfreepress.com/article/20090601/NEWS02/906010319)