It’s a feature that’s been available in the US for some time, but at last us folk on the other side of the pond can get our hands on Facebook VoIP calling.
Now available in the UK Facebook Messenger iPhone app, it allows you to call your friends over 3G or WiFi (via Cult of Mac). If you have an unlimited plan it is extremely useful, but it doesn’t end there.
Facebook has also added voice messaging, so you can record short voice clips and insert them into your normal Facebook chat/message.
The new feature should just appear in the app automatically, so no update download is required.