The nearest major city is Denizli, where you will likely arrive first before getting to Pamukkale.
By plane
Closest airport is Denizli - Cardak Airport is 65 km or 1 hour away and there are flights twice daily to Istanbul.
Izmir Adnan Menderes Airport is another alternative to the area. Pamukkale is 252 km from the airport, a drive of about 4 hours 4-1/2 to 5 hours by busor 6-7 hours by train. Check TCDD (http://www.tcdd.gov.tr for train schedule.)
By train
The nearest train station is in Denizli, which currently has services from Izmir only. The Istanbul service Pamukkale Express was suspended in 2008, presumably because of track renovations, and it is not certain when/if the services will re-start.
By Dolmuå
From Denizli bus station, take a dolmuÅ, a type of cheap communal taxi that usually seats about 10 but it's possible they'll squeeze in more, from nearby Denizli. Frequent mini-buses serve the village of Pamukkale in a 20 minute ride. It cost 3 YTL per trip.It is also possible to make rezervation the bus ticket from Pamukkale Village. And the bus company can arrange shuttle bus to bus station if there is enough number of people.
By bus
Bus to Pamukkale/Denizli can be found from almost all the cities of Turkey. Bus services include water, hot drinks and a snack.There are virtually no bus companies that take you directly to Pamukkale despite what the ticket sellers tell you. The bus will drop you in Denizli and then you have to get on the free minibus to Pamukkale about 20 km away.