Whats the difference between MMS and SD cards?

I know that MMC cards (MultiMedia Cards) are interchangeable with SD (Secure Digital) cards... but what is the difference, and why would I want to pay more for the SD cards, if the MMc cards work?
Any help from you guys that understand would be gratefully received

 

Hi, I found this information on a PDA forum and think it may help you. My Sharp cam uses MMC / SD as does my Handspring PDA, and I can swop the cards between them. I have only used MMC not the SD.

I find the time to save a still to MMC is a bit slow sometimes, so an SD card may improve that.

Follow this link to read about it

http://www.geocities.com/romidar/mmcvssd.htm

Neil