iPhone: If you're a Facebook user who also happens to own an iPhone, the social network's iPhone app is one of the best out there, and today it got a little better, adding push notifications and contact syncing to your Address Book.
Before this version, you'd need to actively open up the Facebook app to get updated on your social happenings at Facebook — despite the fact that push notifications have been around for a while on the iPhone. The new push settings allow you to customise what events will warrant a notification, so you can keep notifications for new messages, for example, but skip notifications for every new comment.
On the contact syncing front, the update allows you to add Facebook profile pictures and links to your existing iPhone contacts. It does not appear to create new contacts if you've got contacts on Facebook that aren't in your Address Book, but the profile image syncing alone is pretty handy.
Facebook 3.1 is a free download for the iPhone.