Re: Getting Gengar, Alakazam, or Golem in FireRed?
No, without trading there's no other LEGALLY way to get these Pokemons. You need another Gameboy, game catridge and a link cable.
If you're using the Emulator you can trade depending the software. VisualBoy Advance Trade Link is capable of making the links between two Pokemon games (it was going to be two windows so).
Otherwise, you could use GameShark, ActionReplay Codes, but that's not legal and may corrupt the progress of your game, use them at your own risk.