Finally, someone made a "Time Zones" clock that is easy to use. You can search using the cities/countries in the list or directly by placing your cursor over the map... it will start rotating and you just have to click over the time zone you are interested in. Easy, isn't it?
I got it from Poodwaddle.com and they offer many many other clocks, from clocks for meditation to a "world clock" that allows you to know how may people are being born by the second, the minute, the week, the month or the year, among other interesting things.
They also provide calculators, stats counters, countdown clocks, feedback forms and many, many more tools for free.
Worth a look.