Earlier this year Condé Nast Traveler updated and re-published their 2008 article on tipping etiquette.
As the article notes, tipping rules vary by country, by region, and by scenario but fear not as this article tells you all you need to know.
Etiquette 101: Your Guide to Tipping in 50 Countries.
The guide offers suggested guidelines for tipping for a variety of services travelers are likely to use and offers some helpful information that is unique to some countries / regions.
BosGuy 