Note that if your Kubuntu install is a VirtualBox guest you need to start it with a normal start if you want the shared clipboard to work. If you start headless or detachable the shared clipboard will not work (in my experience).
If your Kubuntu install is not a VirtualBox guest you can skip the virtualbox-guest-* package installation above.
So to create an alias to an SMB share on your Mac desktop:
First use Finder -> Go -> Connect to Server…
Enter a location such as: smb://server/share
Then use Finder -> Preferences… -> Show: Connected servers
The SMB mount should now be visible on the desktop. Right-click the share on the desktop and choose ‘Make Alias’. Then take connected servers out of your Finder preferences and rename the desktop alias probably as the name of the share.
I managed to get my desktop settings so that files on the desktop were sorted automatically. But I didn’t want that. I edited the ~/.kde/share/config/plasma-desktop-appletsrc file and set the sortingStrategy=0 and that disabled automatic alphabetical desktop sorting.
I wanted to run an application on my desktop when I dropped some files on it. To do that I created a process.desktop file like this:
I seemed to be having a bit of an issue with my nvidia video card driving the Ubuntu Unity desktop on my new Ubuntu 11.04 desktop installation. I found how to disable unity on ubuntu and am now running the Ubuntu Classic desktop which so far has been stable.