How to change time and timezone in iPhone simulator?

I'm guessing it uses your system timezone, so changing the TZ in System Preferences would probably do the trick

Restart the Simulator after changing the system date time preferences and you shall see the changes reflected. It worked for me.

It would be useful if Apple provided a "Simulate date" as they provided a "Simulate Location" menu. What I do is set a breakpoint immediately after getting the date (saving it in a variable) and then modify the value. Or just modify the spot where I check for a date change and make it return true.