The Austrian Internet Foundation has funded Digium to add ENUM to the
Linux-based Open Source PBX, Asterisk (see www.asterisk.org and
www.digium.com).
With a PC and an ISDN card you can build a PSTN, SIP and H.323 capable
ENUM-aware PBX system, which is an excellent vehicle for getting aquainted
with ENUM (and do least-cost rouiting, while at it). Such a system was used
during the IETF 57 Demonstration in Vienna
(http://enum.nic.at/documents/AETP/Presentations/Austria/0017-2003-07_ENUM-Demo_ietf57.ppt).
I will give a talk on Asterisk & ENUM at tomorrow's RIPE tutorial in
Amsterdam. It is intended to convey a basic understanding how Asterisk
works, and how to configure a PBX with ENUM.