He was the easiest to pick off first. It was also a bonus that he happened to be right next to Iran. You know the old saying "Keep your friends close but keep your enemies closer". We now have Iran semi-boxed in from the south and west. I would bet the overthrow of the Iranian regime is one of our top priorities once the Iraq elections are held. Iran is hungry for a democractic government.
Korea is a totally different animal. They are likely less stable than Iran. With the right pressure from China, Japan, South Korea and the USA they wouldn't last long. Plus, they have an easy path to take since they would be reunited with South Korea. They will likely go the way of East Germany. A united Korea would probably give up the nukes to keep from having an arms race with Japan and China.
We are living in a time when history is being made. All this is basically the fallout from the world losing one of the two super power governments (Soviet Union) in the early 1990's. The power vacuums created from this are still being filled and refilled. The Middle East was one of, if not the major, fronts in the cold war. What we are seeing is the start of democracy in this region of the world. After Iraq I think the Palestinians are next. They appear to be tired of fighting now that Arafat is taking a dirt nap. When the Israelis and Palestinians work out their issues it will remove a major irritation from the Middle East. Also, the countries that aligned themselves with the former Soviet Union are finding their options are very limited now. Peace with Israel is becoming their only option.
I think we tend to look at current events in too short a time frame. Changing the course of the Middle East governments can not happen in a few years like it did in Eastern Europe. We now expect instant gratification for nearly everything. It will take decades for democracy to infiltrate fully through this area of the world. In the end though it is vital for this to happen for there to be a lasting peace for our children and grandchildren.