Skilled workers and professionals - Who can apply
Skilled workers are people who are selected as permanent residents based on their ability to become economically established in Canada.
Federal skilled worker applications are assessed for eligibility according to the criteria set out below.
For your application to be eligible for processing, you must:
have a valid offer of arranged employment, OR
be an international student enrolled in a PhD program in Canada (or graduated from a Canadian PhD program within the past 12 months) and meet certain criteria.
Note: As of July 1, 2012, CIC has temporarily stopped accepting applications for the Federal Skilled Worker Program (FSWP). This temporary pause does not apply to those with a qualifying job offer or applying under the PhD stream. We will likely start accepting applications again when the revised FSWP selection criteria take effect. Proposed FSWP changes should come into force in early 2013.
http://www.cic.gc.ca/english/immigrate/skilled/apply-who.asp