Well not conisdering the right to live and work in Europe you will have to:
If you have under 800 hours you will basically start again. You will have to take a certified course which is (or alteast was) called 509. This course is design to teach you to fly right seat. It takes 18 months, and includes 200 hours flight time, and all the ground to take the numerous (13) written tests. It cost about $50,000 but after it you are ready to start applying.
If you have over 800 hours, you only have to take the written test and checkrides, not the flying portion of he course. There is a self study written test course, however it is very hard, your elternative is a regular ground school. There is nothing like the gliem where you can study your questions, you certainly have to know you stuff. The checkrides will be very similar to the FAA ones, although there are some differences flying in Europe so you will need some time to adjust to the changes.