Multiple Django Admin Sites on one Apache... When I log into one I get logged out of the other
Let me guess, is this running on your localhost? and you have each site assigned to a different port? i.e. localhost:8000, localhost:8001 ..?
I've had the same problem! (although I wasn't running Apache per se)
When you login to the admin site, you get a cookie in your browser that's associated with the domain "localhost", the cookie stores a pointer of some sort to a session stored in the database on the server. 
When you visit the other site, the server tries to interpret the cookie, but fails. I'm guessing it deletes the cookie because it's "garbage".
What you can do in this case, is change your domain
use localhost:8000 for the first site, and 127.0.0.1:8001 for the second site. this way the second site doesn't attempt to read the cookie that was set by the first site
I also think you can edit your HOSTS file to add more aliases to 127.0.0.1 if you need to. (but I haven't tried this)
I have two Django projects and applications running on the same Apache installation.  Both projects and both applications have the same name, for example myproject.myapplication.  They are each in separately named directories so it looks like .../dir1/myproject/myapplication and .../dir2/myproject/myapplication.   
Everything about the actual public facing applications works fine.  When I log into either of the admin sites it seems ok, but if I switch and do any work on the opposite admin site I get logged out of the first one.  In short I can't be logged into both admin sites at once.  Any help would be appreciated.