This depends on the version of ArcGIS you have. The compressive "Learning 3D Analyst" course seems good (i did the equivalent Spatial Analyst course version) but it is specific to versions 9.2 and 9.3. I believe there is a classroom equivalent (ungodly expensive) but it is very new and only available in very few locations.
I don't think those 3 courses cover as much material as the 21 hour course but there have been significant changes to 3D analyst in version 10 so the 9.2/9.3 might be too outdated.