What are the requirements for an American to immigrate to Canada?
Emigrate!
Ooh! I came in here for the same nitpick! 
But I think it just applies to the title, I think the statement in the OP is right.
Correct me if correction is needed, but it would be:
Emmigrating from America to Canada
OR
Immigrating to Canada from America
Right?
Wrong. It would be “emigrating”, not “emmigrating”.
Oopsie. Sorry about that. That’s what being up all night and watching your favorite candidate lose will do to you.
So what would I need to do to move from America to Canada?
Yes, would someone actually answer the question, rather than nitpicking?
Start here.
I’ve already been asked this by one person tonight…
Probably the best place to start is the Citizenship and Immigration Canada/Citoyennéte et Immigration Canada website here.
The requirements are described in detail there. A key aspect of qualifying to emigrate is your score on a points scale which evaluates your level of education, work experience, age, and knowledge of English and/or French. It takes a few other factors into account (your spouse’s work experience and education*, whether you have relatives in Canada, etc.). Currently, you must get a score of 67 on the test to qualify. There’s a self-assessment test here.
Americans with college (erm, university) degrees and at least a year or two of work experience in a skilled field shouldn’t have too much trouble getting 67 points. Some knowledge of French would be very helpful too. In some cases, willingness to go to a part of Canada more in need of immigrants can be an advantage. Licensed professionals (MDs, lawyers, etc.) from many countries sometimes have difficulty practicing in Canada, but that’s probably not true of Americans. A lot has been made about shortages of doctors recently, so an American doctor who feels strongly enough about tonight’s results to take a substantial pay cut could probably emigrate very easily.**
*: Spouse or common-law partner. For married/common law couples, the more qualified partner’s score is used in considering eligibility.
**: I don’t think the legislation for this has been passed yet.
Does anyone know what an American lawyer needs to do to be licensed in Canada? Thanks.
Emigrating (not immigtrate) to Canada is very non-trivial. My intent is not to nitpick. Some years back when travelling to Canada I used to joke with others travelling to Canada with me when asked on the other side of the border my purpose for entering Canada was “political asylum.” My answer to the customs person on the Canadian side was always “tourism”. I never had anyone from Canadian customs on the other side to do other than to wave me along. Returning to the US, customs on the US side similarly ignored me. Back then (this was pre-9/11), at the Detroit/Windsor border it was pretty wide open. Probably today the Canadians would think I was a terrorist. 
(I would guess on the US side since they couldn’t just send a US citizen back, things wouldn’t be different.)
[For those outside the US unaware, unless things have changed a lot since then, there is no exit customs on the US side of the border. Someone from the US can enter Canada without passing a checkpoint on the US side.]
I don’t know the answer, but I would start here: Federation of Law Societies of Canada - National Committee on Accreditation.
In our system, admission to the bar is regulated by the Law Societies in each province, not the courts. The Federation is not itself a regulator, but a meeting ground for all the Law Societies. In conjunction with the deans of the Canadian Law Schools, they’ve worked out a uniform system for accreditation of foreign lawyers who want to practise in Canada.
For a faster move you might look into a NAFTA visa- if you are on the list of wanted professions and can line up a job. Seems to be a sort of fast track work permit thing.
Having trouble finding the official gov. site. Here’s this American law firm site describing it.
Well, you could contact the State Dept. in Washington, DC, and renounce your US citizenship. Might be kind of interesting if you do it while in the US. Where would they deport you?
The Master speaks: you have to leave the U.S. to renounce your American citizenship.
Some education.
Some skills.
Some work experience.
Some relatives here.
Some patience.
Take the test:
http://www.cic.gc.ca/english/skilled/assess/index.html
you’ll be able to tell if you qualify to apply.