Well, silver can be found fairly readily in redridge--though it's often mined out there...at least on my server--where the orcs are, I can't remember the name of the place; or it can sometimes be found in duskwood, though don't go there looking only for that, because there isn't very much, and it doesn't spawn as quickly as it does in redridge.
For me, iron is a different story. Being only level 27 but able to mine gold makes things a bit more challenging, and I often recruit my guildmates to help me get at the damned stuff. There are really only two places that spawn iron consistantly, one is in a kobold cave in the Arathi Highlands, and the other is on the east coast of Stranglethorn. People always tell me that there's no east coast to Stranglethorn, that I'm either talking about the ogre mound, or Zuk'-bla bla bla, I can't remember the name. Then when I tell them it's the far east coast, they tell me that's the blasted lands. Because very few people know that there's ore on the east coast--or that there even is one--it is almost never mined out...again, on two of my servers anyway. To get to the east coast, you have to swim. Start at Booty Bay, the swim south, folloing the cape around till you're on the east side of Stranglethorn. There are some fairly mean naga looking things, and mean monkeys, and an elite water giant along here, but if you're a higher level then me, and/or careful you shouldn't have any trouble.