I want to get a Magnezone to fill out the 'Dex, I just have no idea where to find the 'magnetic field' to evolve Magneton? Any ideas?
Level it up in the Vast Poni Canyon (on Poni island). The path with the big tree leading up to the first bit of the cave counts as part of the canyon too, so if you use a rare candy on it there you can evolve it before you battle Hapu.
It's is on Poni Island. It's in the Cave before you do the island challenge. where you run into Goldbats and dugtrios. Just level magneton Up one level in there and it will evolve.