A quick test revealed that the Calendar feature on the iPod uses vCal format. So, you can simply export you Calendar in vCal format and then copy it to the Calendar directory on your iPod. When you unplug your iPod, you can go view the calendar, and it will show you all of your appointments.
I've tried this with Palm Desktop, and I'm sure it will work with any other application that can export vCal format.
[Editor's note: I'm not 100% certain this qualifies as an "OS X hint", but I found it interesting and thought others might as well...so here it is!]

