Nuclear Deal Reached With North Korea

Explain to me again why we can reach a nuclear agreement with North Korea and not Iran? Aren't they both part of the "axis of evil":

North Korea has endorsed an agreement to dismantle all of its nuclear facilities by the end of the year, according to a joint six-nation statement released by China in Beijing today, the state-run Xinhua News Agency reported.

The agreement sets out a timetable for North Korea to disclose all its nuclear programs and disable all facilities in return for 950,000 metric tons of fuel oil or its equivalent in economic aid.

Negotiators reached agreement on a draft plan in Beijing on Sunday after four days of six-nation talks. The United States had said on Tuesday it endorsed the plan, but was waiting for approval from other nations involved in the negotiations.