MiniSD cards are made by several different manufacturers including Sandisk and kingston. They were released in mid 2003 as smaller addition to the SD card family. Though these cards were designed exclusively for use in mobile phones they can come packaged with a miniSD adapter which allows cross compatibility with all devices equipped with the standard SD Memory Card slot.
TIP: Be sure not to confuse MiniSD with MicroSD cards which are a different specification and are not compatible with MiniSD or standard SD slots.