A few weeks ago, I wrote about E164.org.
As of Sunday evening, my telephone system was fully integrated with E164.org for inbound and outboung dialing.
When a user places a call, they dial as usual. Behind the scenes, Asterisk does an enum lookup. If there’s an enum entry, the call is placed over IP. If the call fails, or these’s no enum entry, the call proceeds as usual (eg: through my local ISDN lines).
During the initial testing phase, I have Asterisk configured to say “enum lookup successful” if placing the call over IP. So far I’ve only heard those magic words on calls to US 800 numbers, but hopefully that’ll change as time goes by.