Did the Site modeler module get removed from PowerGeoPak??

Site Modeler was removed in SS4, in favor of the OpenRoads site modeling tools.  If you need the old site modeler then you will need to keep an older version for this.  SS2 and SS4 can be installed simultaneously on the same computer.

ok, where can I find the openroads site modeling options?  it that included in powergeopak ss4?  or is it something separate from powergeopak?  I need to know how to make this work.

Open your Tasks dialog - that's where the OpenRoads tools are. They don't look like the Site tools used to, and I'm not entirely sure that all the older options are well represented.

You would Import your TIN to create a Terrain Model of your existing ground, I know that. I'll leave the rest of the explanation to those folks who know what they are talking about.

The workflow for site design in OpenRoads is:

• Create horizontal layout with the Horizontal Geometry tools.  You can also use vanilla MicroStation elements, but give up some automatic update capabilities.
• Design the profiles using the Vertical Geometry tools
• The primary vertical tools used for site design are circled below.  However, any of the vertical geometry tools can be used and when considered together replace the capabilities found in site modeler.

What's not available that you would ave been accustomed in Site Modeler?

• There are no wizards like the pond wizard and roadway network tools.  You can construct everything but you do it more manually without the aid of a wizard.
• Per object terrain model are not automatic.  You might not even need them.  But if you do, then you must create the terrain models for each object yourself using the profiled elements
• There is no FIFO list - any merging of objects is done by merging the terrain models.

My opinions:

• I can build everything I was able to build in site modeler.
• The end result is far better than the result in site modeler because in addition to the final surfaces I also get very detailed rendered models.
• Profile editing is massively easier.
• Because the wizards and FIFO have not yet been replicated in OpenRoads, it takes me about 10% longer to create the models. 

You might find some training materials for site design in LEARN.  Learning the site design workflows is not something I would recommend to self teach. You will probably get frustrated because we all tend to try to learn something based on what we already know.  Many of the vertical tools function similarly to the site modeler tools but, you really need to clear your mind and act like a newbie when learning site design.