The United Nations Security Council has unaminously approved and adopted the resolution imposing sanctions on North Korea for its activity in testing what is now confirmed to be a nuclear weapon. The sanction, after much negotiation and compromise between the US, France, Great Britain, Russia, China, and Japan. The sanctions include a ban on trade in nuclear and weapons technology, on travel by North Korean government officials, and on trade in luxury items. The resolution also declares that North Korea must cease its nuclear weapons program. Basically, the sanctions are designed to affect the government of North Korea, and not the people of that country.
How this will change North Korea's behavior is uncertain at this time, but in the past we have seen that UN sanctions and resolutions have had little effect on the actions of roque governments such as Kim Jong Il's.
The North Korean government will more than likely ignore the resolution, and continue to test nuclear weapons.
China has objected to the resolution's call to inspect cargo entering and leaving North Korea, but as of the time of this writing, they are reportedly inspecting trucks entering and leaving the country. China has the most sway over the PROK (People's Republic of Korea), being its primary trade partner. South Korea has also kept trade open with its northern neighbor, but 80% of the North's oil fuels come from China. The US has nothing to give or take from its trade relations with North Korea, so the most influence on that country does come from China. In order for the UN resolution to work, China must comply with the sanctions it voted for in the Security Council.
There is a lot of political finger pointing going on in the US, but the truth be told, most US politicians agree that it is the North Korean regime that has been developing the neuclear weapons since 1985. The four US administrations since then have tried various strategies, none of which have been successful, and some of which have merely empowered the ruling Kim Dynasty. In the long run, no matter what North Korea has agreed to, the agreement has always been broken.
If all the signatories to the UN Security Council resolution abide by that resolution and enforce the sanctions, this strategy may work, and return some prestige to the UN. But in the end, it is China, not the US which much deal directly with Kim Jong Il.