While Kingdom Hearts' PSP incarnation, Birth By Sleep, seems like a promising and polished piece of work, its upcoming DS entry could best be described as "troubled." Everything about the game, including the name, seems in dire need of improvement before it's ready to ship.
The name, by the way, apparently varies from day to day. 1UP heard that "358/2 Days" is supposed to be pronounced "three five eight over two days," but upon closer examination at Square Enix's DKS3713 event in Tokyo, the proper pronunciation appears to be "three five eight days over two." But either way, it's a cumbersome name that probably means something, but could probably go about expressing that concept in a more elegant and less obtuse manner.