In addition to:
http://theintegrity.co.uk/2010/08/how-to-allow-users-to-install-printers-using-group-policy/

which allows users to install printers shared on the network without Administrator credentials, below are the instructions on how to allow users install local printers on their machines. This comes handy if you want to allow laptop users to install printers at home.

In Group Policy Management Editor go to:

Computer Configuration -> Policies -> Administrative Templates -> System ->
Driver Installation

and edit Allow non-administrators to install drivers for these device setup classes setting.

Enable policy setting and click Show… to specify device types that users will be able to install.

Add following device classes:

{4d36e979-e325-11ce-bfc1-08002be10318}
{4658ee7e-f050-11d1-b6bd-00c04fa372a7}

Full list of System-Supplied Device Setup Classes is available at:
http://msdn.microsoft.com/en-us/library/ff553426%28v=VS.85%29.aspx

Confirm and close policy setting editor.