Pokemon Soulsilver Ar Code: Event Jirachi

This will give you an event Jirachi which will unlock a new world on your Pokewalker.

Press L+R to activate & enter a Pokemart. Talk to the man in the green suit & he'll give you the Jirachi.

94000130 FCFF0000
62111880 00000000
B2111880 00000000
E0009E4C 00000104
00020001 00000001
00000001 53F10000
DC68369C B5610420
C5C1AB1F 05123687
3B88197C DB96892A
FEB748E0 6A909AEB
DDD83396 DC2C7736
30BBB73A 3626B9D8
83D61AA5 C6CE099F
9402641E 1430E3DE
26BB0DEA 65E5CC4E
25261D00 E7BC7784
5FFFE89D 37BB6CB1
5FE66955 1DA56A1F
985DDD33 AB896096
0EB70954 F22F0D62
DB75E0B5 C22F799F
67A2B8A0 F2F3CE22
AC2141C6 1FAED2EB
B6B879FA 37B64AF7
DE460C22 92F95736
22317837 D4E459C1
82413E98 FF91B194
3CD5D027 02E7D2AB
9924107D D7934469
742B3167 A857A728
138B2BCE 26D8ABF6
975673D6 C1B333EB
D8372D49 062303D5
EEB0FDA5 0AB9A8B3
474E9945 00000000
00004000 00000000
D2000000 00000000

Pokemon Red/Blue: Missingno. & The Infinate Item Glitch

THIS WILL NOT DELETE YOUR SAVE FILE

Talk to the man who shows you how to catch Pokemon in Viridian city. Answer no, and as soon as he has finished speaking fly to Cinnabar Island. Surf up and down the right hand side of the island, right on the shore. You will encounter Pokemon over level 100 and a glitched Pokemon called Missingno or M. The former, if used in a battle other than a link battle, will 'grow' to lv.100.
The latter can affect your hall of fame, graphics, etc. It will evolve into a Kangaskhan if it levels up. 
On encountering Missingno/M the item in the 6th slot in your bag (hint- put a master ball/rare candy there) will duplicate, providing you with over 100. This glitch can be used again and again if you run out, giving you an infinite supply. 

Pokemon Red/Blue: Mew Glitch

When you reach Cerulean city go to the Pokemon center, do not fight the trainer past nugget bridge (he has a lv.17 slowpoke and is facing north, standing above a female trainer) but fight the others so they won't get in the way. Do not fight the man west of nugget bridge either. 
Catch an Abra with teleport (best to have a Pokemon with sing to make this easier). 
Save your game (you won't be able to until the next part is completed). 
Now, cross nugget bridge and head west. Stand just above the trainer's line of sight (so that a step down will bring him onto the screen and cause him to challenge you). 
Step down and simultaneously press start, then use teleport. He should see you just after you teleport away. 
Head back and fight the trainer with the slowpoke (without facing any others on the way). He must walk up to you or the game will freeze. 
Use teleport one more time. Your start menu will be disabled. Then walk back up. As you start to cross the bridge the start menu will pop up by itself. Press B and you will enter a battle with a lv.7 Mew.
Catch it. (If you faint/ run out of balls, you will have to reset and repeat the process)
This works with some other trainers too and the move fly instead of teleport, but this way you can get Mew on your first visit to Cerulean.