Topic: Mega Memory Pak is it compatible with Gamecube gameboy player and Super Gameboy?

I'm getting one for christnas but I'm not sure if it would work with my Gamecube or even GBA SP.

If it fits, it will probably work.
According to the photo on this page, it probably will.
(note that the Super Game Boy uses the extra pins on the connector and probably won't function, correctly if at all, if connected through a SNES cheat device)