How to travel with a small dog?

I'm planning on getting a chihuahua (and before anyone asks, not from a puppy mill). My lifestyle allows me to travel to other countries sometimes. What kind of papers does a dog need to travel with me? Is there such thing as a doggie passport? Is it easy to travel with a dog, customs wise? Anything else I should know?|||Before your Chihuahua will be allowed to travel, she will need a health certificate signed by your veterinarian no older than ten days prior to the departing flight date. You will need to show this certificate before you will be allowed to travel. And your dog should always ride in the cabin with you.|||If you come to Britain she'll be in quarantine for 6 months. We have doggie Passports to allow travel to other European countries, but if you come from outside the European Union, then that's the situation.|||I think you need a pet password and vet checks to travel aboard


and it mostly depends on the airline