Pistachios are a high desert tree.
To grow and bear fruit they require very hot summers (more than 600 hours >30C); very cold winters (more than 1,000 hours <7C); and well-drained soil.
Summer and autumn rains may induce fungal problems and harvest difficulties.

A good summary of growing pistachios under Australian conditions is in the book: "A Handbook for Farmers and Investors", published by the Rural Industries Development Corporation:
Pistachios

Another excellent source of information is the University of Californian Fruit and Nut Research Information Centre's on-line manual: Pistachio Production Manual, 4th edition, 2005.

Nurseries that supply grafted pistachio trees (male and female):

Sunraysia Nurseries
Sturt Highway
GolGol NSW
(5 mins across the border from Mildura)
Phone: 03 5024 8502 (International 613 5024 8502)
Fax: 03 5024 8551 (International 613 5024 8551)
Postal: PO Box 45 GOL GOL NSW 2738
Email:enquiries@sunraysianurseries.com.au
Website: www.sunraysianurseries.com.au/other_var.html

WA Pistachios
Pistachio Nut Tree Nursery
"The Farm" Hooper Road, Grass Valley (via Northam)
Postal: PO Box 429 Northam WA 6401
Telephone Enquires: 08 9622 9513 | Fax 08 9622 9513
Mobile: 0428 181 689
Email: wapistachios@wn.com.au
Website: www.wapistachios.com.au