(Windows Utility) Game Genie Guy! is out.

This is a small Windows utility for applying Game Genie codes to roms. This saves you the trouble of having to enter them each time the game is played.
http://srktt.com/files/GGGuy.exe
Usage:
1. Click the Browse button and select an unzipped Game Boy/Game Gear/Genesis/NES/SNES rom
- The system dropdown should populate based on the file extension
- The checksum box will also be enabled for non-NES games
2. Enter the desired codes, one per line
3. Click Patch when all codes have been entered
4. Open the created 'File GG.rom' in an emulator to test
Checksum:
uCON64 is used for checksum correction. This is required if you are using flash carts. Most emulators are not bothered by it. I recommend the MinGW version because it has no dependencies.
Download ucon64-2.0.0-win32-mingw-bin.zip and extract ucon64.exe to same folder as GGGuy.exe:
http://ucon64.sourceforge.net/
Notes:
Not all codes like being applied in this fashion. Ex: Contra Hard Corps 99 lives work fine while infinite lives does not. If you do not get the desired result try another code.
8 digit NES codes are preferrable to 6. 8 digit codes contain validation that ensures the game is being patched in the right spot. 6 digit codes just go for it. Applying too many 6 digit codes can make a game crash. Try fewer codes if this occurs.
Use BIN or GEN roms for Genesis/Mega Drive. SMD roms are not supported.
Troubleshooting:
If you can't get a code to work try the following:
1. Try a different code. If another code works then the file is being patched properly.
2. Try a different rom - look for a good dump (!) or use Nointro roms.
3. Try it with CCCGP to see if it works. If it does let me know with the full rom name and code you are using. I'll check it out.
http://crackerscrap.com/projects.php
Why would I use this instead of CCCGP?
Tiny standalone file (60KB) - no DLLs/dependencies/registry writes
System auto-detection based on the rom's extension
Original files are copied to avoid overwriting: mario.nes - mario GG.nes
Auto-fixes checksum if uCON64 available
Always on top for easier pasting of codes from browser
Simplified code input doesn't require description
Full source code provided
Thanks to:
cracker: CCCGP
WyrmCorp: UGGCONV/source
Lazy Bastard: tutorials
John David Ratliff: tutorials
Tony Hedstrom: tutorials
Zazer: ggconv
Maël Hörz: HxD
References:
http://gamehacking.org/library/114
http://www.videogamesource.com/genie/gg/gghandbk/p12.html
http://www.ticalc.org/cgi-bin/zipview?92plus/asm/source/ggdecodesrc92.zip;snes.txt
http://romhack.wikia.com/wiki/SNES_header
Source code is provided. BCX and LCC are required to compile:
http://www.bcxbasic.com/
http://www.cs.virginia.edu/~lcc-win32/