Pokémon GO is now available in 26 new countries.

UPDATE: Pokémon GO now available in Canada! Canadians start downloading and join Pokémon frenzy!

 
As Australia, New Zealand, United States, and the United Kingdom have been enjoying Pokémon GO, Niantic has officially release the mobile hit in 26 new countries.
Everyone in Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Greece, Greenland, Hungary, Iceland, Ireland, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Romania, Slovakia, Slovenia, Sweden, and Switzerland can now download Pokémon GO on the Play Store or the App Store.
If you’re noticing problems with the game not loading don’t worry because you are not alone. The servers have been getting overloaded since they released the game all over Europe. The team has stated they are working on it and will provide more updates later.

In case you were wondering, from an ad that was released in September it was already confirmed that a trading system was being worked on and public events to capture legendary Pokemon like Mewtwo, Mew, etc.