For the core MS fonts:
sudo apt-get install ttf-mscorefonts-installer
You may be asked to accept the license agreement, i was not asked.
They end up in /usr/share/fonts/truetype/msttcorefonts
Next is to install the clear types such as calibri
This is a bit different but can be done with the vista fonts installer script. Make sure you have the appropriate permissions.
Create a .font folder as the script needs that.