Yes, they are listed as tradeskills in every other description. You do need trainers in order to increase in level and to gain the ability to smelt different ores, and not all the trainers are at the cities.
Greenie, I've asked for the same information in the "What would you like to see added to the site" list. In the meantime, I've found it helpful to search "mining trainer", "skinning trainer", and "herbalism trainer" in the search box to the left to find the necessary people.
Hope this helps,