I recall reading an article a few months ago that stated FiOS was going to switch its phone services over to VoIP in the future (2010?). To be honest, Verizon's phone service/features (like voicemail, call logs, call forwarding, etc.) are woeful compared to those offered by my VoIP service Viatalk...and I only pay $199 for two-years of service for ViaTalk vice $45 a month for Verizon. Verizon used to offer a VoIP service (VoiceWing?) for $40-$45 per month, but I no longer see it offered on their website (probably because of FiOS).
Here is the article about FiOS' plans to offer VOIP...it was written in December 2008 - yes, over a year ago.
Verizon FiOS getting VoIP in early 2009 - FierceVoIP According to the article, FiOS VOIP is supposed to be in "limited" circulation in VA and MD. Our FiOS service is in TX and we're still using the POTS model. FiOS customer: do you have FiOS POTS or VoIP?
As much as we love FiOS---phone, Internet and TV have been 100% reliable for almost 2-years---the phone systems (features) is a joke compared to the features being offered by VoIP at half the price.