How is the NFL Schedule set?

From Wikipedia:

Currently, each team's 16 game regular season schedule is set using a pre-determined formula:
Each team plays the other three teams in their division twice: once at home, and once on the road (six games).
Each team plays the four teams from another division within its own conference once on a rotating three-year cycle: two at home, and two on the road (four games).
Each team plays the four teams from a division in the other conference once on a rotating four-year cycle: two at home, and two on the road (four games).
Each team plays once against the other teams in its conference that finished in the same place in their own divisions as themselves, not counting the division they were already scheduled to play: one at home, one on the road (two games). This schedule guarantees that all teams will play each other at least once every four years, and will play in every other team's stadium at least once every eight years.

Not from Wikipedia (from me)
Each conference is given an INTRACONFERENCE division to play and an INTERCONFERENCE scheduled to play.

In 2007 AFC North faced off against the AFC East and (intraconference) and NFC West (interconference)