Source
From the announcement:
Your votes are recorded immediately and may be changed up until the time voting closes (11:59 PM CST - February 17, 2014).
The final voting will resolved using the Schulze method.
As usual, voting is restricted to either supporting users (having a supporter badge from any year is sufficient) or voters who pay a one-time 20 GeekGold fee, or users who have purchased an avatar.