Aimed at letting users share contacts more easily between different services, Google Contacts works like any other contacts function. You can import and export your contacts from other sources such as Outlook, Outlook Express, Yahoo, or Hotmail. For Apple you must use a utility called "A to G."
If you are part of a business, school or other organization using Google Apps, the administrator will have to enable this functionality within the control panel by clicking on the "add more services" link, finding the "Contacts" option and clicking the "add it now" button.
You can find the stand alone contact manager here.