Yeah. Some moves you can only teach by talking to tutors or using TMs and HMs... They're like discs you break over your Pokémon's head.

[To demonstrate, he'll scoop out his reusable Solarbeam TM.]

Downside to TMs is that they're typically one-use only. Still, you can get a handful of them at the Goldenrod and Celadon department stores. They aren't required for a tough Pokémon, but they definitely help.