WDTBD is correct in saying that BCC headers
should only used by the submitting MTA (Mail Transport Application: thats the mail server that takes the message from Outlook and distributes it to all of the recipients -- usually identified as the "SMTP" server in your mail application.) The header should be removed by that MTA
before transmitting your message to any recipients -- that's the whole point of the BCC: header, after all. The standard which defines how internet email works says:
The "Bcc:" field (where the "Bcc" means "Blind Carbon Copy") contains addresses of recipients of the message whose addresses are not to be revealed to other recipients of the message. There are three ways in which the "Bcc:" field is used. In the first case, when a message containing a "Bcc:" field is prepared to be sent, the "Bcc:" line is removed even though all of the recipients (including those specified in the "Bcc:" field) are sent a copy of the message. In the second case, recipients specified in the "To:" and "Cc:" lines each are sent a copy of the message with the "Bcc:" line removed as above, but the recipients on the "Bcc:" line get a separate copy of the message containing a "Bcc:" line. [ ... ]
Finally, since a "Bcc:" field may contain no addresses, a "Bcc:" field can be sent without any addresses indicating to the recipients that blind copies were sent to someone.
If it's still there, then the sending MTA is
seriously broken, at least with respect to Internet Standards. Of course it's just possible that your receiving MTA (the server, e.g. at you ISP, where your mailbox lives, that holds the mail until you collect it with LookOut, Eudora or whatever) is adding a BCC: header with just your address in it, for some reason. That would qualify as just
broken, not
seriously broken 
[For those with insomnia, the "rules" by which internet-compliant mailers are supposed to play can be found in the notorious document named
RFC2822 -- if that doesn't send you to sleep, nothing will
]
To view the headers actually present in an email, you need to different things, depending on which mail client you use.
For Lookout!, sorry Outlook, you need to open the message, then click
View,
Options, then look in the box labelled
Internet Headers.
For Outlook Express, try opening the message, then go
File Properties and click the
Details tab.