I would prefer to work with my GBA and Mac OS 10.6 Snow Leopard, but I've also got a GBC and a Windows XP machine hanging around.
Hands down the easiest way that I have found is to get a Nintendo DS that has the Game Boy Advance slot (original and DS Lite), and a slot-1 flash cart.
After that it's just a matter of downloading some software. Linfox is great for that.
NOTE: I would stay away from the M3 solutions for this task because one of the better backup programs, written by Rudolph, was updated to single out the M3 and refuse to backup the saved game.
Alternatively, there are (or at least were) solutions –
– that will plug right into a computer. However, this is a much more technical, difficult process.
As I discovered recently, This can be easily accomplished with the Retron 5 Gaming System:
Copy Save to RetroN 5
The RetroN 5 will allow you to save your games onto the internal storage, as well as the SD card. By doing this, users will be able to extract their saves via the SD card and store them onto their PC. This also allows for users to exchange saves among other owners of the RetroN 5.
Copy Save to Cartridge
The RetroN 5 will allow you to transfer your saves from the Internal Storage or the SD card to your cartridge, allowing you to play your games without losing your save on any other console or handheld.
- Retron 5 Instruction Manual
- Insert your cartridge into the Gameboy/Colour/Advance slot
- When the game has loaded, Enter the Game Menu:
- Click either 'Copy Save to Retron' or 'Copy Save to Cartridge', depending on which action you wish to take.
As quoted above, You can then also copy saves to/from the Retron via the SD card slot.
This will work for all Game Boy, Game Boy Color and Game Boy Advance cartridges, as well as NES, Famicom, SNES, Super Famicom, Master System (via Power Base Converter) and Mega Drive (Genesis) carts that support a 'save' feature.