In Jorvaskr on the east side of the city's Residential district.
Go to the companions in Whiterun and do all there quests they will offer to turn you
You have to go to the Companions in Whiterun. After a few quests they will turn you into a werewolf.
Whiterun, it's the Companions meadhall, Jorrvaskr.
Go to Whiterun and join the Companions. The offer of becoming a Werewolf is part of their quest line.
Join the Companions in Whiterun and do a few of their quests. Probably about the fifth quest you will have access to the ability.
At Shearpoint located to the northeast of Whiterun. There is also a dragon there to so tread lightly.
Right by the pet shop in Whiterun.
Look on your map smart stuff
The Bannered Mare Inn in Whiterun.
It's right next to the stables.
Skyrim has no class system, so how you define a 'barbarian' might be different from others. The Companions in Whiterun are probably the closest to the archetypical Nordic Warriors, you'll find trainers there for various melee skills, including weapons, shields and armour.
The nine holds of Skyrim are; Eastmarch (Windhelm) Falkreath Hold (Falkreath) Haafingar (Solitude) Hjaalmarch (Morthal) The Pale (Dawnstar) The Reach (Markarth) The Rift (Riften) Whiterun Hold (Whiterun) Winterhold (Winterhold)