GDEmu is the actual board. GDMenu is the GUI you use to load games.
GDMenu doesn't even have anything to do with Dreamshell, and the 2 are not mutually exclusive. Dreamshell is for the IDE HDD mods, and the tiny serial SD adapters. Not for the ODE's. The 2 released ODE's both use their own exclusive menus.
https://www.youtube.com/watch?v=yKyH6GPoKvc
You can get the latest update here.
http://assemblergames.com/l/threads/unofficial-deunans-gdemu-thread.57247/page-16#post-902531
Edit: This should also be helpful letting you know how to install the device. HOWEVER! That is a bit outdated, and it is NO LONGER REQUIRED to rename all games as disc.gdi or disc.cdi. It was fixed in later versions.
https://www.youtube.com/watch?v=04jclR41s0A
Oh I see, great stuff, thanks :)