This is another goodie from Sven Slezak at Mezzo.
Link
Thus any highlighted number in an app that supports services can be dialed.
You will need to install the Asterisk Preference Pane on your Mac as well.
Mezzo's Modules Page
The Scripting package includes a scriptable Application for use in AppleScript called AsteriskScripter.
Usage:
You can call the AsteriskScripter from AppleScript:
Code:tell application "AsteriskScripter" dial "01723764958" quit end tell
Link
AsteriskScripter is now also a system service.
Thus any highlighted number in an app that supports services can be dialed.
You will need to install the Asterisk Preference Pane on your Mac as well.
Mezzo's Modules Page