Weaponsmith is in IF, I think you need to have lvl 40.
Don't know if you need a special skill level, I did it many weeks ago ;)
Swordsmithing, Hammersmithing OR Axesmithing (you only can learn on of three, so choose wisely) is been given by a quest in Winterspring. Swordsmiths have to kill the smith in Stratholme, Hammersmiths I think another guy in Strat, and Axesmiths need a kill in Scholomance or Blackrock.
Don't know if there is a level restriction. Maybe 55 because Strat, Scholo and BR are highlevel dungeons.