Boy, what a busy time of year. A music teacher's work is never done around now :)

Like many music teachers, I am involved in many concerts around this time of year. From time to time I like to record some of our shows. Here are a couple of things that I do to help get our shows recorded nicely.
I use a small digital audio recorder called the Edirol R-09. It gives great sound quality and is small enough to fit in my pocket. Before we begin playing I will lay the recorder on a chair or a music stand close to the stage, turn it on and let it do its thing.
It seems like every parent these days brings along a video camera to their children's shows. I never have a problem getting some video footage.
When I get the video footage and my audio recording I combine the two in iMovie or Windows Movie Maker. By combining the audio and video this way I get a great audio signal rather than the one captured by the parent's camera.

To edit the audio I sometimes use Audacity. This is a great free audio editor. Oftentimes I get my students to do the editing of our concert recordings. This is a great little project and they have WAY more patience than I do for these sorts of things.
Andrew