If you apply using the outland method - no work permit is available as part of the process. Having said that, the process is significantly shorter (less than a year). If you apply inland and submit an open work permit along with your application - your open work permit will be approved approximately four months after you submit the application (assuming your status in Canada is valid and you haven't overstayed your visit). However the process is significantly longer (plan for 2 years).
For Americans it's generally much better to apply outland.
If you want to work sooner, you'd have to find an employer willing to offer you a full time job before you can apply for a work permit. That employer will also have to obtain an approved LMIA if you job does not fall under NAFTA (the LMIA process can easily take 4-6 months).