What's the End Game for the Attack on Libya?

After weeks of backing away from military action, the Obama Administration suddenly signed on to the United Nations effort in Libya. The massive attack on Libya began after the UN Security Council passed a resolution on Friday authorizing "all necessary measures" to protect Libyan civilians, short of putting western boots on the ground. Today, the US Commanding General, Carter Ham, says that's still the mission, and that the coalition is not supporting forces opposed to Moammar Gadhafi. But what is the ultimate goal? Is it to topple Gadhafi? Can the rebels do that alone? What if he's able to hold on to power? What's the role of the Arab League, Britain and France? Is the Administration itself divided?