I was googling for info on the VOIP 999 issue and came accross this Offcom Statement which sounds very encouraging. In it Offcom acknowledges that their role is to ensure the public are informed about the differences between traditional and IP based telephony services. They are also trying to encourage existing VOIP suppliers to offer 999 services by not asking them to me the current strict regulatons that traditional phone companies must meet.
They seem sensitive to the fact that VOIP has the potential to benefit the consumer by reducing costs and increasing comptition. If they continue on this track I would say VOIP has a bright future in the UK.
Other countries are not so fortunate, Canada have just introduced regulation for VOIP services, Mark Evans has blogged about it here. Jeff Pulver has also just blogged about his fears for USA VOIP and interference that may come in the form of 'National Security' and the fact that it is easy to encrypt conversations over VOIP.