Torterra: A'Tuin - In Discworld, it's the turtle that carries the world on its back.
Dialga: Kronos - Obvious.
Heatran: Furnax - Roman godess of ovens.
Ninjask: La Mojca - A misspeling of "La mosca", meaning "the fly" in Spanish.
Medicham: Zas! - Comes from a Family Guy episode in Spanish where Peter said "Zas! En toda la boca!" (that's "Zas! Right in the mouth!", I'll check to see what he originally said in English).
Edited: Found it. "Pow! Right in the kisser!", a reference to Jackie Gleason.
Smeargle: Jihad - Substitute+Belly Drum+Explosion. Hehe.
Hippowdon: Arrakis - The desert planet in Dune.
Vaporeon: Jocántaro - A sea monster in the Spanish B-movie "Karate a muerte en Torremolinos"
Drifblim: Sustitocho - "Sustituto"=Substitute, "Tocho"=Huge.
Lopunny: Travelo - He was a male Lopunny, you can guess what "travelo" means then.
Dunsparce: LOL HAX - This one is pretty obvious.
Seriously? I named my Dialga Chronos!!!!