It sounds like you usually sync your iPod to a Mac, and want the synced iCal events copied to a Windows box. Otherwise you would not have calendars on your iPod in the first place.
The problem here is that a single iPod is not meant to sync with more than one machine at a time. It is an extension of one computer, holding music and calendar events until they are overwritten during your next sync.
The most efficient path is in syncing your iCal to Google Calendar
, which could then be viewed on any computer, Windows or otherwise. Ergo, iCal is your schedule's source, copying itself to your iPod and Google Calendar separately.