It's easy. All you need is an emulator (I'm using VisualBoyAdvance) the Japanese ROM (extremely easy to find with Google) and the patch. Put the ROM and the patch in the same folder, execute the patch, and you're good to go.
Yeah, I know, I'm going to hell for pirating the ROM. But seeing as they have no plans to bring it over to English territories, and I have no plan to learn Japanese, I suppose I can get used to a lake of fire.