Right now it consists of my previously-published demo songs. However, now you can subscribe to them with a program like iTunes (version 4.9 or higher). Then, whenever I add a new track (and I have some ideas for the next few days), you'll get it automatically, and it can go straight to your iPod. Cool, eh?
How do you subscribe? The easiest way, once I've indexed it there, is to search for "penmachine" in the iTunes store's Podcast directory (see instructions). Otherwise, you can click and drag the orange and grey "RSS Podcast" button or the address https://www.penmachine.com/rss/podcastmp3.xml to your iTunes window (or other podcast subscription program). Get the latest version first.
Alas, I won't be in the iTunes Podcast Directory just yet:
UPDATE: See the fix for that problem.