I see what you're looking for now.
There's a small diamond-shaped handle at the top and bottom of the dendrogram. By dragging that handle you identify a given number of clusters. The vertical line in the scree plot shows where the point for the selected number of clusters.
The distance for that point would be is in the Clustering History table below the scree plot.
You can see it a bit better if you drag to make the scree plot bigger. Here's a small movie showing the interaction.
-Jeff
-Jeff