You can download the full miniatures rules from here:
http://www.wizards.com/default.asp?x=dnd/mi/20031023x
That also has the FAQ, which answers your question somewhat:
Q. How is the skirmish system different from the Dungeons & Dragons roleplaying system?
A. In general, the skirmish system is a streamlined version of the D&D roleplaying system, simplified so that it's easier to run several different creatures at once and play through a battle quickly. Here are some specific features of the skirmish system.
Command: Without commanders, creatures are slower and more likely to run away. Commanders also give specific bonuses to their followers.
Morale: Creatures that are reduced to half hit points or lower sometimes run away (rout). Commanders can try to rally creatures to stop them from running.
Initiative: Each round, you roll initiative for your whole warband. You don't roll for each individual creature. Each round, players take turns each activating two creatures at a time until all the players have activated all their creatures.
Targeting: You usually shoot, cast a spell at, or charge the nearest enemy. You can't just pick off the enemy commander.
Damage: All damage and hit points are measured in multiples of 5. An Ogre, for example, has 30 hit points and deals 15 points of damage with its greatclub.
Saves: A creature uses its level as its bonus on saving throws.
Attacks of Opportunity: They're easier to keep track of. There's no 5-foot step, no limit to the number of attacks of opportunity per round, and no attacks of opportunity for reach attacks.
Cheers!
