Are there any tutorials for setting up multiple instances of DNN on the same server I was hoping to load another instance with the newest version.

It's not a problem at all.  Just:

• Create a new directory and copy the install package. 
  
• Create a new database on your SQL server.
• Create a new website and point it at the new installation

Your biggest hurdle will be to set up DNS for the new site.  What I generally do is set up another alias, newsite.mydomain.com.  Point the newsite.mydomain.com at the same IP as all of the other sites.  They are, after all, on the same machine.  Your website should use the same alias and the IP of the server.  IIS will route requests to the correct website on the server. 

I have perhaps a dozen (probably more, actually) installations on one machine.  No problems at all.

If you don't want to go the separate website route, set up all on the installations as Virtual Directories under the default website.  That way, there won't be any need to configure DNS.  Your sites will be mydomain.com/installation1, mydomain.com/installation2, etc.

If you are doing it on localhost, mydomain.com becomes localhost. 

If you want to visit the sites from another computer on your local network, use the IP address (make sure that portalalias for the sites includes the IP address version).  The alternative is to use the computer name instead of the IP or localhost name.