Windows movie maker is the easiest. It comes on most newer machines, but its also a well known fact that the damn thing crashes like 85% of the time so あなた have to have alot of patience.
It really depends on what type of video you're going for. Windows Movie Maker is a good one if you're aiming for a simple, no-fuss video. If あなた want to make もっと見る complicated ones, like fanvids, then Sony Vegas Pro 9.0 will definitely help. I found a thread on the Gossip Girl spot, which might help あなた with videomaking.
