In
Windows Phone 7, you have some control over how your contacts list
looks. For example, you can change how you sort or display names. You
can also filter out all but your most important Facebook friends by
electing to show only people who already have a contact card on your
phone.
1. Hide Facebook Friends
On the Start screen, flick to the Apps list, and then tap Settings.

Flick to Applications, and then tap People.

Under Include Facebook Friends As Contacts, tap Only Add Facebook Info To Existing Contacts.

Press the Back or Start button on your phone to exit.
Warning:
This option affects only the
contacts list. It doesn’t affect the posts shown in What’s New. Also,
when you search People, you might see Facebook friends who are hidden.
2. Change Sorting Style
In Settings, flick to Applications, and then tap People.

Do one of the following:
Under Sort List By, choose whether you want the list sorted by a person’s first or last name.
Under Display Names By, specify how you want your contacts to be listed.

Press the Back or Start button on your phone to exit.