Although this thread is quite old, I'd like to add a little update since I came across it. Using Facetime while connected to a WIFI network will not result in any fees. Facetime does not deduct airtime or minute from your Fido plan but does use data/internet therefore if not connected to a WIFI network you will be charge once you've gone over your data allocation and if roaming outside of Canada then data Roaming fees will be charge.
Data usage is approximately, more or less 3 MB per min.
Facetime = Apple VoIP service = data/internet usage, which can result in data overage fees & data roaming when outside of Canada.
Hope this helps!
Just to let you know that , today I noticed that Fido has charged me 230$ for calls that I made via FaceTime using my home wifi . how is it possible?
however I have a large data plan (8 GB) which I only had used around 4 GB .