Code:
Break On
$oRoot = GetObject("LDAP://RootDSE")
$strDomain = $oRoot.Get("DefaultNamingContext")
$objOU = GetObject("LDAP://CN=Users,ou=MYOU,"+$strDomain)
;If the default users ou has not been changed this should work
;Otherwise put in your FULL OU path and remove the RootDSE lookup.
'Get OU Path error: ' + @SERROR ?
$objOU.Filter = "user, "
For Each $objUser In $objOU
  If $objUser
   'User: ' + Right($objUser.Name,-3) + ' has the company set as: ' + $objUser.company ?
;   $objUser.Put("company", "new company name")
;   $objUser.SetInfo
;   Removing the above 2 commented lines and putting your company name in should work
  EndIf
Next
 



Break On
$oRoot = GetObject("LDAP://RootDSE")
$strDomain = $oRoot.Get("DefaultNamingContext")
$objOU = GetObject("LDAP://CN=Users,ou=MYOU,"+$strDomain)
;If the default users ou has not been changed this should work 
;Otherwise put in your FULL OU path and remove the RootDSE lookup. 
'Get OU Path error: ' + @SERROR ?
$objOU.Filter = "user, "
For Each $objUser In $objOU
  If $objUser
   'User: ' + Right($objUser.Name,-3) + ' has the company set as: ' + $objUser.company ?
;   $objUser.Put("company", "new company name") 
;   $objUser.SetInfo 
;   Removing the above 2 commented lines and putting your company name in should work 
  EndIf
Next