How can I change the link in the left hand pane of the printers pane?

Start the Active Directory Users and Computers MMC snap-in (Start - Programs - Administrative Tools - Active Directory Users and Computers)

Right click on the domain and select Properties

Select the Group Policy tab

Select the 'Default Domain Policy' object and click Edit

Expand Computer Configuration - Administrative Templates - Printers

Double click 'Custom support URL in the Printers folder's left pane'

Select Enable, and set the URL Title and URL, click Apply then OK
Click here to view image

Close the Group Policy and the MMC snap-in