Xboo loader
Use the XBoo cable to upload a file to a GBA
This is a command line application to upload a file to a Gameboy Advance (GBA or GBA SP). It can work on Windows, Linux and *BSD platforms. It uses the parallel port, and can use PCMCIA, PCI and PCI express parallel port adapters. It won't work with USB to parallel adapters.
See this video for another alternative using the USB port.
https://www.youtube.com/watch?v=Zfmj_KPE_L4