displays a user's friends' three most recent updates on the home page
has a dedicated page to display all your friends' updates at once
has an RSS feed aggregating all of a user's friends' updates
offers the ability to subscribe to a friend's updates via SMS
offers the ability for a user to update their status by sending an SMS to Facebook starting with the "@" character
In fact the only Twitter-like omission is the ability to update a user's status via an IM client -- perhaps to encourage users to stay logged-in to Facebook.
I've privately speculated that Twitter would have made a pefect Facebook acquisition. But with the technology being fairly easily replicated, it probably makes more sense for the social networking site to roll its own. Which is exactly what they appear to have done.