virtualbox.org

So when you install a linux guest and you install the guest additions, do you install on both linux and windows? I ask cause there is the linux ones in there and the windows .exe's. Are those only for windows guests?

Just let the installer do its thing. It will choose the right binaries to install. As a further explanation, the guest additions have all the necessary files for Linux, Windows, and Solaris. None of these will install on anything else but the appropriate OS so it will not install an exe on a Linux and will not install an sh on Windows OS, Etc..

i meant do i need to install the linux additions on teh linux guest and the exe on the windows host?

That is your decision. You can run without but it will not be optimal.

See http://www.virtualbox.org/manual/ch04.html

It's called Guest Additions. Why would you want them in your Host?

The Guest Additions provide guest drivers which make the guest OS integrate better with VirtualBox, e.g. allowing simple shared folders and drag and drop.

Guest Additions have no meaning on a host.

heh thanks guys. In my defense, I was thinking maybe there was some kinda drivers or something needed host side to work with the guest side stuff.

OK, not a bad thought, but the means to communicate with the guest are already built in the program and they are installed when you install VirtualBox.

Yes, there is an extension pack provided for host side stuff too. But, for obvious reasons, those are not called guest additions.