Palmerston North is 7 hours by car from Auckland and two hours from the capital Wellington on State Highway 1 SH1.
Palmerston North Airport (http://www.pnairport.co.nz/) handles domestic travel as it lost its status as an International Airport in 2008.
It is also on the main railway line between Auckland and Wellington. There is a daily service - The Overlander. See the article Train travel in New Zealand.
Naked Bus (http://nakedbus.com/) offers the cheapest land transport option into Palmerston North with fares starting at $1 if you book early enough.
