For an overview of tango events and classes in CHRISTCHURCH, plus extensive links on a range of topics: 
http://www.tango.gen.nz/site/events/
http://www.tangovibe.co.nz/

FIND MORE TANGO in New Zealand:
http://www.tango.gen.nz/
http://www.tangonz.org/
NZ Tango Festival: http://www.nztangofestival.co.nz/

MILONGUERO style tango:
For classes in Buenos Aires - La Academia de Tango Milonguero: http://www.laacademiatango.com/content/quienes-somos
Practimilonguero Blogspot - includes video interviews with milongueros in Buenos Aires: http://practimilonguero.wordpress.com/

MUSIC:
Todo Tango - for info about the tradition, orchestras and musicians: http://www.todotango.com/
Zivals, music store, Buenos Aires: http://www.tangostore.com/home.php?lang=e
Buenos Aires Tango Club, music store: http://www.buenosairestangoclub.com/