I'm not sure about the previous poster... But the accepted manner is as follows:
As Tim said earlier, 'p.p.' stands for 'per pro' - or, in its full glory, 'per procurationem'.
This is Latin and means "on behalf of". Therefore, when using 'p.p.' to sign on someone's behalf, you would end up with -
Yours sincerely,
(Put your signature here)
p.p. Mr Bloggs (Their Surname)
- i.e. this is You, signing on behalf of Mr Bloggs.
Also (and purely for your reference), the accepted space to leave between 'Yours Sincerely' and the sender's title (in this case, Mr Bloggs) - the gap in which you would put your signature - is five empty lines long.
![Smile [:)]](/emoticons/emotion-1.gif)
Jemima Little