The Windows Live Dev website has a new entry entitled New! Windows Live Contacts Gadget (beta) which states

Learn how, with nothing more than a little JavaScript, you can allow customers to use their Windows Live Contacts (Hotmail/Windows Live Mail and Messenger contacts) directly from your Web site.

To get started check out all of our developer info, the two working samples we’ve posted, and read the blog posts by one of the guys who developed it: Danny Thorpe.

What the gadget does is pretty simple yet powerful. It allows you to add a gadget to your page which logged-in Windows Live users can use to retrieve information about their Windows Live Messenger or Hotmail contacts and then input that data into your service. Think of it as adding a form fill or address auto-complete functionality to your site which uses that person's address book from Windows Live services to power it.