virtualbox.org

Is it possible to create a dock icon that will launch a particular VBox machine?
I've found that Vbox will allow you to create a shortcut on the desktop that will let you launch a particular machine, but so far, I've not been able to find a way to make a dock icon for the machine.

just drag the .vbox file for whatever VM you want to the document side of the dock.

btw, there is a very handy free piece of software for Macs called VirtualBox Menulet which gives you a drop down menu in the menubar of all your installed VMs. You just have to select the VM you want to launch from a list.