Elastix:

Elastix is a Distro with Asterisk 1.4.17 with lot of features

feature list
The features provided by Elastix are many and varied. Elastix integrates many software packages, each including their own set of great features. However, Elastix adds new interfaces for control and reporting of its own, to make it a complete package. Some of the features provided natively by Elastix are:
VIDEO support. You can use videophones with Elastix!
Virtualization support. You can run multiple Elastix virtual machines on the same box.
Really friendly Web user interface
"Fax to email" for incoming faxes. Also, you can send any digital document to a fax number through a virtual printer.
Billing interface
Module for automatic outgoing campaigns
Graphical configuration of network parameters
Resource usage reporting
Remote restart/shutdown options
Incoming/outgoing calls and channel usage reports
Integrated voicemail module
Voicemail Web interface
Integrated operator panel module
Extra SugarCRM and Calling Card modules included
Download section with commonly used accesories
Embedded help interface
Instant messaging server (Openfire) integrated
Multi-lingual support. Languages supported include:
English
Spanish
Rusian
Korean
Greek
Chinese
Polish
German
Frensh
Romanian
Slovenian
Portuguese
Danish
Italian
Mail server integrated including multi-domain support
Web based email interface