Keep In touch - Keep in touch with thousands of people
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
The Contact Guru - Managing your contact list so you don't have to
Google Calendar - Spend less time managing your day & more time enjoying it
Cardhop - The Mac contacts app you'll want to use.
Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.