Apple's "Address Book" is included with OS X and is part of the "triumvirate" which also includes Mail.app and iCal.app, gives you the ability to drag address cards to Mail, where they are automatically pasted in their vCard, or VCF, form.
Problems Sending vCards to Windows Users
In trying to send VCFs to Windows Outlook users, I discovered two problems by trial and error. First, the Windows users could not open what I was sending even if it was in English, and second, the Japanese fonts in the vCards were garbled. The bottom line? Use Format version 2.1 for the greatest compatibility and set your language accordingly.