The Retweet feature has arrived to Facebook. The feature currently works on links posted by your friends. You cannot share their status updates or photos. If you friend shares a link you can then click the share button found below their link and a "Via friends Name" pops up. If you do not want to share your friends name you can further remove the "via" and just share.
The Retweet does not work exactly like Twitter in that you can share without your friends name. So you can now share links posted by your friends and choose whether you include their name or not.
You can also choose before posting whether you would like your friends to use the 'Via' option.
Facebook's Twitterfication gets deeper.