As of January 2015, Citizenship and Immigration Canada (CIC) has a new electronic system called Express Entry to manage applications for permanent residence under certain economic immigration programs.
The Express Entry system is the first step to immigrate to Canada under these programs. Potential candidates can complete an Express Entry profile at any time. Note that there is no deadline to complete a profile and there are no caps on the number of candidates that will be accepted to the pool.
Anyone who is accepted into the Express Entry pool could get an Invitation to Apply for permanent residence. Draws to invite candidates to apply will take place regularly over the course of each year. CIC will only pick the top ranking candidates no matter when they were accepted into the pool.
If you are invited to apply, you will have 60 days to submit a complete Application for Permanent Residence online.