I have recieved an email from 'two' people on a number of occasions in hotmail. The IP addresses are the same when the 'people' have sent the email on the same day. Does this mean that this is really the same person ???

Perhaps this page will help:

http://www.johnru.com/active-whois/trace-email.html

The Recipient's email server (POP3, Yahoo, Hotmail, etc.) receives the email message from the original sender's server. (e.g. bay15.hotmail.msn.com)

1. A 'Received: from [sender mail server] by [recipient mail server]' field is appended to the top of the current sequence of Header strings.
2. Any previous 'Received' Headers will appear below this new one .
3. The newest 'Received:' Header at the top of the sequence of Headers now contains the IP address belonging to the email server of the sender; (e.g. Hotmail.com) It is not the true IP address of the sender himself.