A while ago, I blogged about the tax consequences of being American outside of the United States. Americans are taxed based on citizenship, and so Americans living in Canada still have to file their taxes with the IRS, even if they have become Canadian citizens and have lived in Canada for years. If they don’t, they can be charged with tax evasion, particularly since there are special rules for Americans with foreign assets (including their everyday Canadian bank account).
Recently, the IRS announced that they are extending their amnesty program for Americans with foreign assets who have never declared these assets. For Americans living in Canada who were unaware of the need to file, this is welcome news. The former amnesty program expired in September 2011; this new amnesty has no expiration date, which will allow Americans living in Canada who were unaware of the consequences of not filing the chance to bring themselves current with their US taxes. You can read an article about this in the Globe and Mail.
If you are an American citizen, you should see an accountant to ensure that your filings are up-to-date.