As the head of my family and of my venture tool CouchTycoon I´m a frequent traveller too. The site I just found called DOPPLR is perfect for me, my family and business partners. DOPPLR in their own words: "How does Dopplr work? It lets you share your future travel plans with a group of trusted fellow travellers whom you have chosen. It also reminds you of friends and colleagues who live in the cities you're planning to visit. You can use the service with your personal computer and mobile phone."