I also believed, as you stated above, that a user would need elevated rights of some kind to make some changes to AD but I have just logged in as a standard user in our domain and exectued this following code:

 Code:
Break on

$x = ADSIUserInfo()

$x

sleep 2

? "Set the telephone number attribute"

$y = ADSIUserInfo($x,"telephoneNumber","12345678")

sleep 2

Exit


via Kix32.exe and it seems that the telephone number has been updated on this standard user, as expected! (not sure if that highlights a problem with our domain, or whether this is expected behaviour for this particular attribute).

Cheers