Reaching out to a global audience with a web conference is an effective way to deliver training or hold a meeting. When planning synchronous events for global audiences here are a few key questions to ask regarding the logistics of your event and online resources to help find answers:
What are the time zones of the participants?
Make sure that you schedule your event during a time that's convenient for participants.
What are the national holidays in the countries of the participants?
Check these online resources so you don't schedule an event during a public holiday in another country.
http://www.state.gov/s/cpr/rls/dpl/63099.htm (US State Department list of national holidays)
What is the legal work week in the countries of the participants?
Monday - Friday is the work week in the US, but not the entire world. In Muslim countries the work week is different to allow for Friday as a day of prayer. http://en.wikipedia.org/wiki/Workweek