How does the NFL playoff schedule work?

For each conference (AFC and NFC) the four division winners receive the 1 through 4 seeds, ranked according to their season records. The two wild card teams (the teams with the best records that did not win the division) receive the 5 and 6 seeds. Example from the NFC after the 2007 regular season:
1. Cowboys 2. Packers
3. Seahawks 4. Bucs 5. Giants 6. Redskins During the Wild Card Weekend, 3 hosts 6 and 4 hosts 5. One game is played on Saturday and one on Sunday. Teams 1 and 2 get the week off (referred to as a "bye").
The following weekend is the Divisional round of the playoffs. 1 hosts the lower seeded survivor from the Wild Card round, and 2 hosts the higher seeded survivor. Again, one game on Saturday and one on Sunday.
The winner of the Saturday Wild Card Game will play their next game on Saturday. For example, the Seattle Seahawks beat the Washington Redskins in the Saturday wild card game and they will play the Green Bay Packers on Saturday in the Divisional playoff. Leaving the Dallas Cowboys to play the winner of the New York Giants vs. Tampa Bay Buccaneers on Sunday.

The next weekend is the conference championships. The higher seeded survivor from the Divisional round hosts the lower seeded survivor. The winner goes to the Superbowl to face the winner of the other conference.