Found the Guide to ITM Teams from a couple of years back, so may be a little dated (2010 vintage).
Please advise me of any necessary edits & I will update.
Last Updated 2 September.
Credit to Scorez and Paarl Bok for producing this material.
From North to South, most teams and some past or present players:
Northland Taniwha - Maori mythical demon-like creature - likes swamps and dense scrub/bush. Peter Jones, Sid Going and his brothers, David Holwell, Ian Jones, Norm Maxwell, Rene Ranger are names from the Kauri Country. Australia's own Tui Fa'asisila from Parramatta's Mighty Two Blues will be playing with them in Season 2012.
North Harbour - No nickname, split off the Auckland Union because of too many good players in the area. Buck Shelford, Ian Jones, Glen Osbourne, Walter Little, Frank Bunce, Luke McAllister, Nick Evans, Tony Woodcock, Australia's Salesi Manu from Warringah/Western Force will be playing with them in Season 2012.
Auckland - They are known as Auckland, the Jaffa's (Just another f-wit from Auckland), Orcs, A's. nothing really sticks. Used to have a mascot elephant named "ARU" - geddit? Players like Steve McDowell, Fitzpatrick, Dowd, R Brooke, A (spit) Haden, G Whetton, A Whetton, Zinzan Valentine Brooke, David Kirk, Grant Fox, Joe Stanley, John Kirwan, Terry Wright, Afoa, Mealamu, Kaino, Toeava, Rokocoko... In the 80's, 90's hugely strong. Not so much of late. Supporters many but mostly outside of Auckland because no-one from Auckland actually lives there.
Counties-Manukau - Steelers - Jonah Tali Lomu. Nuff said. Fritz Lee, Tim Nanai-Williams, coached by Tana Umaga, Kieran Read was poached from there. DJ Forbes - NZ 7's supremo plays for the Steelers.
Waikato - Mooloo's - Dairy farming area, hence the mascot - a cow. Supporters take cowbells to the ground and all opposition fans love to hear the racket when they are shaken in support of a Waikato attack or when the oppo kicker is trying to kick a goal. Great people, Waikato fans. Richard Loe, Graham Purvis, Warren Gatland, Mark Cooksley, Keith Robinson, John Mitchell, Deon Muir, Brendon Leonard, Rhys Duggan, Ian Foster, Matthew Cooper, Richard Kahui, Sitivini Sivivatu, Mils Muliaina, Todd Miller, Roger Randle, Liam Messam, TKB are two more recent names.
Bay Of Plenty - Steamers - Large retired population. Struggle to name any players aside from Mike Delany and Tanerau Latimer, Sam Cane, Brodie and Callum Retallick
of note. Uncharitably known as Bay Of Pensioners.
Hawkes Bay - Magpies. George Nepia to Zac Guildford, or better Israel Dagg, Hika Elliot,
massive history.
King Country - Rams - Sir Colin Meads is from there. Nuff said.
Taranaki - They have a bull mascot called Ferdinand who has been around since at least the early 60's, but it's not part of their nickname. Bull Allen, former Taranaki player and AB, post dates Ferdinand. Jason Eaton, Andrew Hore, Craig Clarke, Beauden Barrett and Andre Taylor, plus a few others. Currently have the Ranfurly Shield.
Manawatu - Turbo's. Think it's a recent nickname from their marketing dept. Have a bunch of supporters called "Bucketheads" who wear a bucket with eyes cut in on their heads to the games. Carlos Spencer and IIRC Christian Cullen both from there, as is Aaron Cruden. All the Whitelocks are from there.
Wellington - Lions - have a lion in their logo, they've made it more prominent now. Tialata, Rodney So'oialo, Ma'a Nonu, Conrad Smith, Cory Jane.
Tasman - Mako's - Newish amalgamation of two former rivals - Marlborough and the other one. Nickname is all marketing. Sort of a salary haven for the Saders, Chris Jack now plays there, as does Ben Franks and a few other names that escape me. Australia's own Peter Betham (Syd Uni/Rebels) will be playing for them in 2012. Jeremy Sua (former Two Blues junior) also played for Penrith and Wests, Australia Schools, Waratahs academy and Samoa.
Canterbury - Cantab's, Red-n-Blacks - Bit of a magnet for talent, they have the Deans family, Grizz Wylie, Wayne Smith, Graham Henry (!), Steve Hansen, Dan Carter, Richard Hugh McCaw, etc, etc, etc. Like Auckland, many people don't like Canterbury.
Otago - No Nickname, used to have fanatical "Scarfie" supporters. Not so much nowadays. Strong in the shamateur days because they have a University with a good culture. Marc Ellis, Jamie Joseph, Tony Brown. Others.
Southland - Stags - Resurgent team., Simon Culhane is a past name, these days they are synonymous with Jimmy Cowan, the bogan pisshead halfback for the AB's.
The bits in blue on the NZ map are teams that compete in the Heartland Cup (2nd Division competition)