Emulator Info!
For all general questions about emulation please read the articles and visit the thread linked on this site:
http://emulation.gametechwiki.com/index.php/Main_Page

Emulator Links:

Desmume: This is generally accepted as the best emulator out there at the moment for DS emulation. It should work for most PCs unless you’re running something from eons ago.
Direct Link: http://www.emucr.com/search/label/DeSmuME/

Visual Boy Advance M: An updated version of VBA released to fix some bugs or problems. It plays GBA, GBC, and GB games, so it’s generally considered the go to emulator for all Pokémon games.
Direct Link: http://www.emucr.com/search/label/VisualBoyAdvance-M/

Gambatte: The most accurate Gameboy and Gameboy color emulator out there. For those that HAVE to play it like they remember it exactly. Remember, this is only for GB and GBC games though.
http://sourceforge.net/projects/gambatte/files/gambatte/

Retroarch: A multisystem emulator that has basically been ported to EVERYTHING: PC, Linux, Mac, Android devices, Wii, GameCube, even the phat original Xbox. It has a faster version of VBA as well if your computer is just that bad.
I’m going to assume you’re smart enough to read so please read the articles from here about it if you’re going to use it:
http://emulation.gametechwiki.com/index.php/RetroArch

If you're playing on a computer this should be all you need to play anything your heart desires.

However, if you're on Droid, here are some other options:

See Retroarch above first for GBA and GB

DraStic: A payware emulator that I wouldn’t usually put on here unless someone already cracked it. It’d be a shame if I happen to link that here now wouldn’t I….
Direct Link to what you’ll need to play it and info:
http://emulation.gametechwiki.com/index.php/DraStic

 NDS4droid: DS Emulator. I have to be honest, I don’t know much about this one, but, you can get the latest versions for free. I don’t know how much the supposed mediocre support has been improved, but supposedly it can run most Pokemon games pretty well now. Just make sure to use the in game save feature. There’s also an iOS version (faggot)
Direct Link for Android devices:
http://www.emucr.com/search/label/nds4droid?&max-results=12

Direct Link to iOS version:
http://nds4ios.angelxwind.net/i/?page/downloads


My Boy! Free: GBA emulator that does not support save states in the free version. However, Pokémon has an in game save feature, so put two and two together.

FAQ:
Q: So and so didn’t work…
A: DID YOU FUCKING READ ANYTHING ON THE WEBSITE LINKED MULTIPLE TIMES? IF YOU DIDN’T DO THAT FIRST, THEN ASK THE EMULATION GENERAL, AND THEN IF YOU DON’T GET AN ANSWER THERE FUCKING COME HERE.
Q: Where do I get roms?
A: Are you literally retarded and did not read the first post the whole way through?
Q: It says the internal battery has died/M1 circuit board did not load.
A: In visual boy advance m go to Emulator > Save Type > Flash 128K. You may have to reload the rom or restart the emulator after this to fix it.
Q: DS emulation is slow!
A: Go into the config menu, go to emulator settings. When the next menu opens up look for Dynamic Recompiler, check this on, and put the number to 15 to prevent anything from breaking in game. If you’re still failing to get the speeds you want, jerk it up to 100, but it may cause more graphical glitches.
Q: Heart Gold/Soul Silver crash/freeze/bugs up!
A: I assume most roms on the internet are patched already, but if yours isn’t you need to patch your game with the Rudolph patch. Check the links to official games links pasta for more information. If your screen goes black or the sprites glitch up either go into a menu, or save and reload to fix.
Q: I can’t get exp in Black/White!
A: Same as above, check the official games links pasta.