I don't know anything about geexbox, I use wiiMC. It works great.
I'm about to try out GeexBox for Wii, will it play .mkv, .mp4 and .rmvd videos?
thanks, because I get freezes from MPlayer on the Wii when trying to play .mp4, .mkv videos
GeexBox supports .mp4 and .rmvd but I'm not sure about .mkv.
Copy everything into the root directory of your SD card.