I've written about Finnish parties' place in the political field before (e.g. here and here), but the treatment the topic really calls for is an arbitrarily put together political compass. The exact placements are subjective, but my opinion is mostly based on data found in Vaalit ja demokratia Suomessa by Heikki Paloheimo et al., the Finnish Business and Policy Forum's 2007 Attitude and Value Survey, and the Helsingin Sanomat's election machine's (fi) pretty, pretty maps (fi).
The left/right axis is based on economic issues, the liberal/conservative on social issues.
left -------2--+----------> right
1 Centre Party (Keskusta)
2 Social Democratic Party (Sosialidemokraattinen Puolue)
3 National Coalition Party (Kansallinen Kokoomus)
4 Left Alliance (Vasemmistoliitto)
5 Green League (Vihreä liitto)
6 Christian Democrats (Kristillisdemokraatit)
7 Swedish People's Party (Svenska folkpartiet)
8 True Finns (Perussuomalaiset)
It should be noted that some parties' support is spread more widely than others'. Examples of parties with a diverse lot of supporters are the three most centrist parties, the Centre, the Social Democrats, and the Swedish PP. True Finn supporters are all over the map in their economic opinions and the National Coalition Party voters and politicians display quite a bit of variance on the liberal/conservative axis.