With version 1.5 you can comment on your friends' statuses, link your contacts in your address book, use facebook pics as contact pics, sync facebook events with your BB calendar and more.
There's some more info here: BerryReview
Before you get too excited, this update is for BB's running OS 4.6 only. So thats the Bold 9000 and Curve 8900. Sorry to everyone else, but there is an official update coming for everyone soon and version 2.0 is rumored to be coming by the end of the year.
If you want to get it now, go here on your BB browser.
Or you can download and install it with your Desktop Manager using this link.