There are several programs you can use for free, but most of them all leave watermarks (unless you purchase the full versions). Fraps is awesome for recording, but I don't know if that works for emulator stuff. Sorry I can't be of further use. =/ I know some people use hypercam, but definitely leaves a watermark. xD Doesn't the VisualBoy emulator have a built-in recorder or something? Either that or I'm trippin'. xD

Good luck. :]