Time Zone Pro is described as 'We think it's fairly likely you have at least a couple of contacts dotted around the globe and we know how difficult it can be keeping track of lots of different time zones'. There are more than 25 alternatives to Time Zone Pro for a variety of platforms, including Online / Web-based, Windows, iPhone, iPad and Android. The best alternative is timeanddate.com, which is free. Other great apps like Time Zone Pro are World Time Buddy (Freemium), Time.is (Freemium), timee.io (Free) and FoxClocks (Free, Open Source).
FoxClocks is a Firefox/Thunderbird extension to display local times around the world in your status bar or any toolbar. Virtually all the worlds time zones are supported. FoxClocks also allows you to explore each time zone in Google Earth.