Forgot to mention, I need a GNU/GPL component not a commercial one.

I have already seen Plaxo Invite for CB, I need something similar but it should be freely downloadable.

Hi Jaspal,
I am also searching for one such free web service/API which would allow me to import the address book details - in additon to just email ids (contact list ids)
I require the phone number and other details to be loaded/import to my web page
That is when the user signs in with my site, with a user id and password in my site and wants to share his address book details he already has in say yahoo or other email providers, i should have a service to just get the yahoo/gmail id and password and return the address book details. Similar to what plaxo does - for contact list ids. But in plaxo's case, it only synchronizes the other address book details. I don't think it imports the address book details.It only imports contact list. Second thing for commercial purposes i should register with plaxo which is not preferred.So if u come to know about any web service/ API which would help me to import address book details including contact number etc of the contact list, it would be helpful and great.Please keep me updated.