There's abook[1], but yours seems different in design. (Main difference at a glance: Yours doesn't work on captured interface. So in that sense, yours is more Unixy.) One nice thing about abook is that it integrates nicely with mutt (which I see someone has already asked you about and you're working on).

One thing that might be nice would be an abook to ppl exporter. abook saves its information in a flat file at ~/.abook/addressbook with items like the following:

    # abook addressbook file
    
    [format]
    program=abook
    version=0.5.6
    
    
    [0]
    name=Someone Somewhere
    email=someone.somewhere@gmail.com
    
    [1]
    name=Another Person
    email=another_person@yahoo.com
    nick=Another
    
    [3]
    name=Detailed Somebody
    email=somebody@details.org
    address=2222 Main Street
    city=New Somewhere
    state=NY
    zip=10011
    phone=212-111-1111
    nick=person
    notes=Birthday May 14th

It shouldn't be too hard to convert that, but I'm not sure (yet) about how you're storing information. (You mention vcard, but I'm not familiar with the details of that.)

[1]: http://abook.sourceforge.net/