Yes, my wife is currently living in Canada. Are we required to pay in both countries? Can her or I file as single until I'm a PR of Canada?
I don't know anything about US taxes.
Your wife need to tick the box for married, show the date you were married, your name and SIN (if any), and your income for 2011. Then she completes her return as normal.
If you were living in Canada in 2011 you will likely do the same.