Atavus.com
Seattle Seahawks and top colleges have gone to Atavus for guidance on Rugby tackling.
Atavus also hold top quality rugby camps, including here locally (Winter 2015 at TCU).

Seattle Seahawks Rugby Tackling Video

Seattle Seahawks head coach Pete Carroll
"Seahawks teach shoulder leverage tackling".
This is a SAFE, but effective way to tackle,
while taking the HEAD out of the game.
(Video courtesy of NFL Films).
http://www.theguardian.com/sport/2014/aug/02/seattle-seahawks-coach-pete-carroll-tackles-

Rugby Tackling Skills
- From International Rugby Coach
'Heads-Up' tackling

Urban Meyer at Ohio State wanted nothing to do with 'Rugby Style' tackling.
But the Seahawks video, tried it, and had their best season they ever had tackling.
(see here for full cbssports article)

Canton Football - From last team in district to State Championship, using Rugby to build their football skills.

Boise State turns to local rugby team for tips on safe tackling

(From Yahoo Sports, July 2013)