Here are seven tools that we have used successfully.
World Clock http://www.timeanddate.com/worldclock/ to find out the local time for participants in different parts of the world.
Doodle http://www.doodle.com/ to offer a range of options for the date and time for a meeting and find out the participants’ availability for each – without generating an avalanche of emails.
Time timer http://www.timetimer.com/store/category/1/timers
Timer for iPhone and iPad https://itunes.apple.com/us/app/timer-by-timeanddate.com/id478835051?mt=8&ign-mpt=uo%3D4
Lucid Meetings. http://www.lucidmeetings.com/ Interface available in several languages.