Check out http://www.cic.gc.ca
This is the website to Citizenship and Immigration Canada. Like the US, certain criminal charges can make you ineligible to immigrate while others can be allowed after proof of rehabitation. That used to be a minimum of a 5 year process.
This is definitely a situation in which you should hire a knowledgeable Canadian immigration lawyer, but you may find out if your individual circumstances render you ineligible through the website before you go to the expense of a lawyer.