Hey,
I'm a Canadian engaged to an American (we want to get married to have a life and a future together, not just to live in the same place).
Just to let you know, getting married will NOT make him a Canadian Resident. After marriage, he'll have to apply for a spousal visa, which could take up to 36 months to process. She'll have to meet certain income requirements, and by agreeing to sponsor him, she promises legally to support him for anywhere between 3 and 10 years.
As well, they'll both need to sign an undertaking agreement with the government, underlying their commitments to each other, and they'll need proof of their relationship: pictures together over a period of visits, plane tickets, receipts, letters, e-mails, and affidavits from family and friends attesting to their relationship, and personal knowledge of the sponsoree.
Plus, they'll each have to do a process of interviews, and lying about anything will get him deported, and never allowed back in Canada.
It's a long and trying road, and it's not the one that I would pick, as it's also very expensive (usually in the range of 10,000-30,000 dollars CDN). For more info, check of the CIC (Citzenship & Immigration Canada) at
http://www.cic.gc.ca/english/offices/
Tell her good luck, she'll need it!