In certain circumstances you can sponsor your spouse (if you both are here) from within Canada.
There are certain differences between submitting the application to CPC Vegreville (the In-Canada route) and the 'traditional' route (submitting the application to CPC Mississauga and, after sponsor assessment, to the responsible visa office). One important difference is that there is no appeal of a refused In-Canada spousal sponsorship whereas there is recourse to the Immigration Appeal Division in the event that an overseas sponsorship is refused.
The relevant CIC Manual can be found here.
A helpful flowchart as to the In-Canada process is below (from page 44 of the Manual).
Raj Sharma JD LLM