I've also referred folks to this thread:
http://britishexpats.com/forum/showthread.php?t=421108I suggest that no one knows what the future of overseas filing is for the future. For the moment, no Consulates will accept/adjudicate petitions. Overseas USCIS Field Offices MAY still accept them.
Overseas offices have jurisdiction over the foreign residence of USCs. If you are a USC living outside the US, there is a CIS office that serves you, or a US Service Center designated for you. All of this information is spelled out in the Guide, including the link for finding your Field Office.
The term "DCF" has been misused so many times that it now means different things to different people. Strictly speaking, it is the act of filing the I-130 with a Consular officer under the 9FAM (see
http://foia.state.gov/masterdocs/09fam/09n0200.pdf). As a practical matter, it can mean anything from that, to filing with any foreign office (consular or DHS) or the whole thing down to IV issuance. There are differences between all of these processes though.
If I were a USC living in Canada who was ready to file an I-130 I would wait a few days to let things shake down, and then I'd follow the instructions at the website in the first post of this thread.
If someone is eager to get their case started immediately, the option to file with Vermont Service Center is still open to you. Immigrant Visa cases aren't exactly flying out of Canada at the moment anyway, so where the petition is filed is of less importance.
DeadPoolX: you're right, there is a lot of information and NO information swirling around and most people can't make heads or tails from it. Doesn't that suggest a wait-a-bit strategy to you? IMO, everyone should lay back for a few and see what news comes out; there is no sense in perpetuating misinformation.