<map lat='59.20722764436484' lng='9.622306823730469' zoom='11' view='1' float='right' /> Skien is a city in Telemark, Norway. It's the capital of the county. Famous for Henrik Ibsen, most things there are also named after him. It has a population of 51 369.
If going towards Oslo you might want to head towards the railwaystation. This is the area called Nylende. From here you will be close to the beginning of the Rv 32 (This is a more direct route towards Oslo) going to (and through) Siljan. Ask for the direction to Gjerpen church (Gjerpen kirke). Using Rv 32 you will probably pass through Drammen on your way to Oslo.
If going to Tønsberg, Horten or Oslo by the coastline, it is advisable that you take a local bus that leaves you close to Telemarksporten. Here you will find a petrol station, besides other things. You could ask outside the entrance if someone are going towards Oslo (or your destination). Here is also a favourite stop for truckdrivers. Telemarksporten is situated in Porsgrunn/Eidanger.
See Metrobuss for information on bus routes.
Also check NSB for train schedules. Notice that Skien and Porsgrunn are pretty much left out of the railwayplans of NSB, so they are usually buses between Skien/Porsgrunn and Larvik (Where you change for train). There buses are operated by Nor-Way. They also have independent buses to Oslo, using the Rv 32 road. Nor-Way also have buses going towards Bø.