Once you are married, you will need to sponsor him using the outland spousal sponsorship process. He won't be able to come to Canada until the process is complete and he is approved as a permanent resident.
He will need to have a valid passport in order for you to sponsor him. Additionally, he'll need to ensure he's 100% honest about his immigration history in the sponsorship application.
Sometimes interviews are required for spousal sponsorship. If one is required for your application, you should assume it will take place in your spouse's home country and he will be required to attend in person.
Depending on how long your spouse has been in the US without status, he may be banned from re-entering the US for either 3 or 10 years as soon as he leaves. So if he's been out of status for more than six months, he needs to be prepared to leave the US and then not be able to return for a number of years.
Lastly, it's quite possible your application processing time will be longer than normal due to your husband's status in the US. The chances of an interview are also likely higher.
