Explain: time zone support.

Explain: time zone support. I do not want my iCal appointments to change when I cross time zones. My iPhone is set to network time so it updates with changing time zones. My MacBookPro remains set to its internal clock's time. How can I make everything stay synched when I change time zone? If I set a west coast appointment for noon when I'm on the east coast and then arrive in PST I want that appointment to still be at noon PST. Sounds simple but Mac has made it complicated and counter-intuitive.