Transports to get you to Rovaniemi 

To arrive to Rovaniemi you have some choices: train, car or plane.

If you are in Helsinki and want to go to Rovaniemi spending less money, and if you don't mind travelling at night, then the TRAIN is the best option.
You can check timetables and buy your train tickets directly on VR website:
I must advise you that this is a 12 hours trip but you can sleep without loosing a minute of the day.

If you have a CAR you can drove from any city of Europe to Rovaniemi. It will take you more time to arrive, but you can do some stops and enjoy some very interesting spots in Finland.
You can always arrive to Helsinki airport and rent-a-car and drive yourself safely to Rovaniemi.

The easyest and fast way to get to Rovaniemi is by PLANE. The city airport is 11km (8 miles) away from city center and its very close to Santa Claus Village and Park. Rovaniemi Airport is served by Finnair, Finncomm and other airline companies. During Xmas time there are also other special planes and charter flights from England and other european cities.
You can check Rovaniemi's Airport activity clicking in this link.
At the airport there are the traditional taxis, but the "Airport taxi service" is the best, the most confortable and cheaper way to go to city center, directly to your hotel.
This service costs €7 per person and can be booked in advance through this contact:

Airport Taxi Express +358 16 362 222

Local Transports To Santa Claus

Local bus company is very good and the bus timetamble is excellent, giving you several options to get to Santa Claus Village or Santa Claus Park.
In the city center you must get Santa's Express (number 8 Bus. It statrs in the Railway Station and stops in Rovaniemi main spots (hotels and near the park).
The trip to Santa Claus takes 15 / 20 minutes and be sure to warn the driver where you want to stop so he can let you at the main door of the Park or the Village.
Each trip costs 3,60€ and you can buy the return trip at the beggining for 6,60€, children pay only 1,80€.
You can get the bus timetable clicking here in this link.
You can also ask for a Taxi at your hotel main desk. This is a very personal way to get to the parks, a bit faster but more expensive. A single way ride from Rovaniemi city center to Santa Village can cost you 20€.