Helpdesk as local admin

[WALI <hkhasgiwale () gmail com>]

Hi Guys..

So what's the defined best practise regarding HelpDesk personnel be 
given/told local admin account names and passwords on users PC/Workstations 
in order to undertake routine fault finding and applications installation?

Help Desk techies also regularly inserts new workstations into the domain 
hence they need certain privileges to be able to make new workstations join 
the domain. What could be the most secure way given the fact that Servers 
are running Win 2k3 and client machines are a combination of WinXP and Win2k.