well, i just started playing around with Microsoft's Window Movie Maker (it came bundled). it's not great, but it's intuitive, and you can get going pretty fast. all the videos i've made, i've made with Movie Maker .. it basically has all i need to make simple videos ...
the one thing i wish it had is the ability to lay down more than one layer of sound ... you basically get the video soundtrack, and then one (just one) audio track.
but you can't edit the video soundtrack ... it's either on or off ... and when you're doing voice-overs and stuff like that, it can get real difficult to do
i started making short pieces, and then just kept getting longer ... the key is to get fast at editing, and you can have a lot of fun