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.