How do I only displace the top of a cube and not the sides or the bottom? Would I only unwrap the top plane then. Please explain the best way to do this.
pg
What do you mean by displace? Displace modifier? If so, just make vertex group for part of mesh to be displaced and select this group under modifier tab.
thanks jawra. I read the wiki then tried it in 2.5. I selected the top of my cube only and then created a vertex group and named it “Cube_Top”. I then created a new tex. I then created a Displace modifier and selected the vertex group.
It still displaced the whole cube and not just the top of the cube. Any ideas what I have done wrong?
pg
Try this: Select other verices and assign them to another group, so mesh has two groups of vertices.
Or create and assign group after you subdivide object.
I think, if object is subdivided after assigning group, the group data is lost and it causes whole object to be displaced.
Thanks jawra. Got it working now. 
pg