Local Admin on workstations

I currently have users that only need very limited rights on the network but are constantly installing and uninstalling software on their local NT workstations for testing purposes. At the moment someone with Admin rights has to log in for them eachtime they want to do this. I want to be able to give these users Admin rights on their local machines so they can do these installs themselves but keep the restricted rights for the network. I can’t seem to be able to find a way to do this. Can anyone help?