The following sites offer some useful information for visitors:
http://www.hel.fi/hki/Helsinki/en/Etusivu
http://www.visithelsinki.fi/en
There are several bus connections from the airport to the centre of Helsinki. The trip takes about 30-45 minutes. You can take the Finnair citybus (6.20 €) or the regional bus line 615/620 (4,50 €). The final stop of both lines is the main railway station in the centre.
A taxi from the airport to the city centre costs about 40 €.
For more information, click here:
Helsinki-Vantaa airport
Public transport in the Capital area