sudo apt-get install python-pip; pip install virtualenv; pip install virtualenvwrapper
The above works fine (note that you don't need to sudo the pip stuff, it gets installed in ~/.local) but ~/.local isn't in $PATH by default, so virtualenvwrapper.sh isn't pathed in.
One fix is to using the default ~/.profile behaviour to path ~/bin if it exists:
ln -s ~/.local/bin ~/bin