Yes, you can turn them in to the trainers in PoK. You have to give them to the trainer of the same class that the armor is for. And for the Iksar armor, you have to find the Iksar trainer of that class on the evil side of PoK. You get exp and a gem when you turn them in. Any armor can be turned in by any class. A BP gave me about 4% exp at level 50. BP's and legs usually get blue, raw, or regular diamonds and smaller pieces will get smaller gems. Hope that helps.
I was able to buy these boots off an elf for a mere 1k plat. What a lucky Iksar I am. They have 30 HP by the way, not 30 Mana. Probably they changed that from the day the boots first appeared (would make sense at any rate).
DUH! Of course it has mana, jeez, warriors need all that mana to heal, think about that next time you need a LOM warrior to heal you!!! ha, j/k. Thats pretty stupid. Make it +30 hit points or something, sounds a bit more.....smart.