I took Trixie with me to Europe over Christmas. It went really really really well and I'm so glad I took the time to research it and actually went through with it.
First of all, which country are you going to? The rules depend on the country. I was lucky enough that the Netherlands doesn't have any strict rules. Everything was laid out for me on the consulate-general's website.
Which airline are you flying with? It depends on the airline whether or not they allow you to take your yorkie in the cabin (I would personally not fly them in cargo under any circumstances!) and how much you have to pay.
How does your yorkie do traveling?
Okay, so my experiences. I contacted the Dutch consulate-general first of all to check about the requirements. They told me she did not have to be quarantined as long as I had all the correct paperwork. I had to get a regular health certificate and an international health certificate (which I could print out from the Dutch Consulate-General's website and the vet filled that out). I made reservations with the airline. I flew NWA and paid $125 each way. I borrowed a travel bag from a friend of mine and got Trixie used to it well in advance. I took her out on fun trips in her bag so she would think 'fun trip' everytime she had to go in her bag. Trixie is a great great traveler. She's quiet and can hold her pee a long time. Security at the airport was great. Of course I had to take her out of the bag, going through security and Trixie got lots of attention there and they kept offering to help me out. On my way overseas (the long flight) I was told by the flight attendents I could not take her out of her bag under any circumstances. I cheated a little and took the bag with me to the bathroom and took her out for a few minutes at the time. On my way back to the US, I took her out a few times, because nobody told me I couldn't
Trixie did soooo well. I didn't even have to give her tranquilizers (I had them with me just in case). I put a small fleece blanky in the travelbag and some potty pads in case she really had to go. I gave her a light meal and water before we left and made a whole travel bag for her (filled with treats, potty pads, water dish, toys) that I took with carry on. Even though they said not to give her too much water, I did let her drink quite a bit (I figured, if they tell us to drink lots of water, why not the dog), and I actually gave her licks of Nutrical because she didn't want to eat. She didn't go potty for 14 hours each way. I'm so proud of her... and again I'm so glad she went with me, because she had a great time with my family!