There is a much easier way to get Shinies in G/S/C without using the Shiny Ditto trick. This is especially useful for those who want Shiny Pokemon that can't be bred like Articuno, Lugia, etc.
I got this off of someone a long time ago on a different forum, and I'd like to give credit but I can't remember their name. I'd also like to have posted this earlier, but my memory isn't a good one.
*Pokemon Gold/Silver (I can't remember if Crystal works0
*Pokemon Stadium 2
Sorry to those who don't have their N64 anymore or PS2 (or even a Transfer Pak). :(
Also, I have saved part of the person's post, fortunately, and I'd love to share it with everyone.
When you take a Pokémon out of a box through Stadium 2, apparently there's a glitch where the game thinks it's still in the box. When you put something else inside that box, everything from the removed Pokémon is transferred to the new one. The data combines I guess but the Pokémon who was removed earlier remains dominant in terms of the stats. Specific data like name, DVs, trainer/ID, and PP Ups used for each move transfer to the new Pokémon.
Once I used Entei to pass it's DVs to Lapras. Entei's 4th move was Solarbeam while Lapras' 4th move was Mimic. After I did the trick, not only did Lapras have the same DVs as Entei but it's Mimic attack was replaced with Solarbeam.
My original explanation of the glitch might be confusing so I'll use a specific example. Let's say I want a shiny Magikarp. I have Red Gyarados. I have a normal Magikarp.
All steps must be done through Stadium 2.
1 - Enter the GB Tower so you're playing Gold or Silver on the N64. Make sure box 7 is empty. Put Red Gyarados into box 7.
2 - Save then leave GB Tower mode and go back to the main screen on Stadium 2. Go to Oak's Lab.
3 - Open a list of Pokémon from your party and box 7 only. Place Red Gyarados into your team then save.
4 - Go back into GB Tower and into the PC. Deposit Magikarp.
5 - Switch to another box, but while it says 'saving' hit reset on the N64 around 'sav' or 'savi'
6 - Go back into the game and withdraw Magikarp. While in the box, it may not appear shiny. It may even appear as Red Gyarados. Once you take it out though, you'll see that it's the shiny/golden Magikarp.
I've done it myself, and I'm happy to say it works.
I'm not so sure about files being deleted, since my file is okay and working still, but I suppose it might be possible if you do something wrong.
Update; Here are pictures of a couple Pokemon I've gotten Shiny through this glitch, just to show off and for the skeptics.
(sorry for poor picture quality)
Look at those lovely curtains! And oh, that beautiful shadow is me.