get it hereThe first GBA emulator with link, no$gba, is released for free. But have you never wanted to trade between Ruby and Sapphire, or even between Sapphire and Leaf Green?
Now it's possible!
VBALink is a normal Visualboy Advance 1.6a for Windows, but it supports up to four* GBAs linked together!
Of course it's free (even opensource), so get it, try it, and spread it to whomever might want it.