How do I stop iCal from changing my appointment times when traveling?

Once again I missed an important meeting as I had entered it into my iPhone so that event is to start at 10 AM. Last night I flew to this city which is two hours ahead of my town. So what again happened is that iCal just decided to change the time of my appointment to 12 AM.

Why on earth would iCal asume that I would eneter the event into it in my hometowns time? I mean, when agreeing on the phone with a client, you do not say I'll be there 10 AM my time. You obviously say "ok let us meet at 10 AM".

So how do I stop this from happening.