MultimediaCard (or MMC for short) have more or less been replaced by SD cards (Secure digital). MMC can be used in quite a few devices that supports SD cards (like your camera for example). I think SD cards are cheaper and are available in bigger sizes plus they support higher transfer speeds. My advice is to buy SD or SDHC cards unless you have some other device that specifically uses MMC as well and you want to use the same media.