- Plug in your iPod, being sure you’ve enabled iPod Firewire Disk support in iTunes so that it mounts on your desktop.
- In iCal, choose the calendar you wish to export by clicking on it in the upper-left-hand pane.
- Select File > Export… and save the .ics file to the Calendars directory on your iPod drive.
- Unmount and unplug your iPod.
- Browse your iPod to Extras > Calendars and, if all went to plan, you should be offered the choice of viewing a particular calendar (the one you exported) or All, if you exported more than one.
That should hold nicely until iSync sometime later this month.