ContactSaver

Connect ContactSaver to your Gmail account to start uncovering email signatures buried in your inbox. ContactSaver will intelligently convert these email signatures into contacts and you decide whether to save a contact to your Gmail address book or ignore it. Also checkout http://www.evercontact.com/

http://www.evercontact.com/ does this as a service and is amazing. Interesting to see how this works in comparison. It seems to be free?