I kind of figured it was possible but never tried until today. You can simply drag iCal files to the “Calenders” folder on your iPod. (Mac users can use iSync to do this automatically.)
We are using iCal exported calendars from Goldmine as I’ve talked about before. In an effort to be a GTD person, I’ve been hemming and hawing about going with an electronic personal calendar, but now I think I will (using Sunbird to create ical files). Dragging-and-dropping is a step I’d rather avoid, but since my iPod goes everywhere I go, it should be my tool of choice.