Tracey,
Here's a similar version of the code posted by MP, load the lisp and type LAST-SAVED-BY.
The results seem somewhat unreliable in 2006, (apparently half of our dwgs were created by AutoDesk) not sure if this has been improved in later versions but it's worth a try.
;**************************************************************************************************
; LAST-SAVED-BY - Command to display the name of the last user to save the current dwg. *
; ============= *
;**************************************************************************************************
(defun c:LAST-SAVED-BY ( / )
(alert (strcat "This drawing was last saved by: "
(strcase (vla-get-lastsavedby (vla-get-SummaryInfo (vla-get-Database
(vla-get-ActiveDocument (vlax-get-Acad-Object))))))))
(princ)
)
