It can be achied via GPO by simply altering NTFS permissions on the folder c:\windows\fonts and also on the registry key HKEY_LOCAL_MACHINE\SOFTWAR
E\Microsof
t\Windows NT\CurrentVersion\Fonts
This is a computer based setting, to be found at computer config - windows settings security settings -file system/registry. You have to add the items (c:\windows fonts and HKEY_LOCAL_MACHINE\SOFTWAR
E\Microsof
t\Windows NT\CurrentVersion\Fonts) manually.
People seem to have problems using it, read
http://serverfault.com/questions/86598/allowing-users-to-install-fonts-in-windows-7-through-gpo