You can attach it to your Canadian registered Google account. It just checks for a US IP when registering.

You won't be able to receive calls at all because its just forwarded to the US number you used to register. All people can do is send you SMS and leave you voicemail. If thats okay for you then Google Voice should do everything you want.

The voicemails get sent through speech recognition and then emailed to you along with the raw audio.

The number you choose is free but if you ever decide to change it will cost you $10.