Mobile App: Know what to tip
For detailed information on what to give everyone from concierges and waiters to ski instructors and tour guides in 108 countries and regions, there's Tipping Tips. What's more, the app advises what to give based on both the standards of the destination and the level of service received. And if you're dining with a group, the calculator will break down how much each person owes.
Cost: $0.99.
Runs On: iPad, iPhone/iPod Touch.