Saving API mashup data in OPML files

Now that I can use the Optimal browser to display OPML files easily on a web page, I can go ahead with an idea I've had for creating mashups of API results. I wrote about this on my mashup blog 2 weeks ago, so you can find the details there. I'm going to start coding now, and as usual the details will appear on the mashup blog as I work them out, and the source code will appear on my Ruby blog. I'll report back here when anything interesting is ready for viewing.