WebQuests are another constructivist tool. The shortage of text material for the early grades is glaring. It is there, but hard to find.
Computer game programming is an area where Constructivist learning is practiced. With tools such as Gamemaker and Klik&Play, it is being used in classrooms from grade 3 up
Contemporary Educational Psychology/Chapter 2: The Learning Process provides a discussion of constructivism as it relates especially to classroom learning.