Pasted directly from Outlook's Help File:

Microsoft Outlook supports the use of vCards, the Internet standard for
creating and sharing virtual business cards. You can save a contact  as a
vCard and send it in an e-mail message.  When you open a vCard, it opens as
a contact item, and you can easily save it to your Contacts folder.

In Contacts, click the contact you want to send as a vCard, and then on the
Actions menu click Forward as vCard.