@Jeff, are you using Creo stand alone or in a linked session with Windchill?
If it is the former, then any of the aforementioned methods will work.
If you are using Windchill, select both the drawing and the model in your workspace and do a save as. This will copy the drawing and the model to a new drawing and model. The last step is to go into Windchill and rename the the files to what you want them to be. If you aren't going to use the original anymore, we usually just append it with _obsolete.
Keep in mind that Creo/Windchill currently has a limitation that will not let modified items be copied. I know it's stupid and I've filed a ticket with PTC, but they refuse to acknowledge that it's a bug. It is particularly annoying since that is how a lot of new iterations happen; you start to modify a model and then realize it should be another part entirely. PTC has no easy way to accomplish this right now.