How do I change my keyboard shortcuts in xubuntu?
Keyboard shortcuts are tucked away in your Settings Manager - Window Manager - Keyboard
Scroll down the list - you will see several workspace shortcuts, some defined with a shortcut and some awaiting to be defined.
There are more available in Settings Editor in Settngs Manager, which can be launched from the command-line using:
xfce4-settings-editor
This will display:
For Xfce 4.8 (Xubuntu 12.04 LTS)
Keyboard shortcuts are accessible from Settings -> Settings Manager -> Keyboard -> Application Shortcuts:
Choose "Add" to add a command you need to assign to a shortcut.
In the window following "Ok" press the key combination you want to assign: