"Last updated" line

Hi,

I haven't done VBA programming in Word before (only in Excel), so I thought maybe some of you guys could help me with this simple problem: I have a document which is updated very often by various people and thus it would be nice with a line which says when the document was updated and by whom (I guess there is some kind of function which can get the "word username" or "word initials"?). This code should either be done automatic everytime the document is saved (the best option I guess) or by hitting a "update information"-button.

So all in all I need a line in the top of the document right below the headline like: "Last updated dd/mm/yy hh:mm by username"

I hope I have made sense Thx in advance.