Even in the dry season antimalaria pills should be taken anyway to be safe. Best air access is from Brisbane or Fiji. There are also flights to Port Vila from New Caledonia and Salomon Islands. I highly recommend to use also internet resources. National Tourism Office of Vanuatu has huge and very well organized web page in internet.
Australian dollar is also often acceptable in the shops.
But do not expect luxury there - usually they have share facilities. Domestic airline - the Vanair offers Discover Vanuatu Pass that allows you to visit from the capital three outer islands for USD 236. There are also inter-island freighters but they are irregular. Full day tour by 4WD car - 8000 vatu.