For anyone who has to occasionally schedule a meeting or phone call across time zones TimeScroller is a great little widget and it’s free!
It defaults to the current time but a great feature is the slider at the bottom that allows you to slide forward in time and watch all the zones update. The widget allows you to configure your preferred zones and the order they appear. There is also an email button that will take all the time zones you have set for the current slider time and copy them into an email.
There’s a paid iPhone version if you need a mobile version.