Telephone is a recently launched Facebook application that lets you make free VoIP calls directly from Facebook. There are several other applications that enable you to do this on Facebook and other networks like MySpace and Bebo, but Telephone, launched by BabyTel, is adding a few extra features to hopefully make it worth your while.

After adding the Telephone app to your Facebook account, you can launch the service and make phone calls directly to your Facebook friends. In order to make a VoIP call, both you and your friend will need to also have the application as well as the downloadable software. But the good thing about having the software installed on your computer is that the Telephone app can then be used as a standalone desktop application for sending and receiving calls even when you don’t have Facebook open in a web browser.

Similar to Skype, you can make VoIP calls and send instant messages. And similar to Digsby, the desktop app enables you to communicate with Facebook friends without having to be logged into Facebook. So with so many features similar to existing applications, is it worth it to try the Telephone application at all?

There are a few features that may be of interest to you, depending on how often you need to communicate with Facebook friends. For instance, Telephone allows you to organize friends into groups for easy access and messaging, as well as leave voicemails for friends that aren’t currently available to talk. Telephone also displays your call history for additional information. The call history could prove useful given its direct integration with your Facebook network, offering insight into your own personal behavior and communication patterns.

I imagine such data could be useful to other services as well, from a non-personal standpoint. But one thing I’d love to see on the Telephone app is a more direct integration with Facebook’s existing chat tool, similar to Tokbox’s integration. This way, you can invite friends to add the Telephone app in a more direct manner, and more readily initiate VoIP calls with friends as well.

While the application is robust, it doesn’t appear as though the uptake has been good. A quick look at the application chart shows that traffic to the application has dropped significantly over the past month. While we’d assume that this trend will continue, perhaps the company will adopt practices that make the application more viral under the new design. For now we will have to wait and see. Go install the telphone application and judge for yourself how successful this will be.