[CentOS] Recording piano and voice

The last time I wanted to record a voice announcement on my computer was a few years back, and as I recall I hooked up my Microsoft Lifechat headset and used Audacity to do the recording.

Now I want to record a "recitation", which consists of me playing my piano and talking over it.

I have a Casio CDP-230 digital piano but I've never tried hooking it up to my computer and making a recording. It does have a USB midi port on it, but I've never used it.

Has anyone else done something like this? I'm wondering what the easiest way to simultaneously record from a microphone and a digital piano would be.