I seems to me (I don't have the software - not availabke now) that "Scratch" will be an easy way for the creation of Squeak applications by kids, that can be made "multiplayer" using a Croquet island. This can be made graphicaly without any line of code by any kid having Croquet installed.
To know how to put a Squeak application ("project") inside a Croquet island, read the DMU tutorials serie at:
http://www.dmu.com/crb