Cingular has introduced "push to talk" features on its GSM network. When
Rogers introduces the feature, assuming it is also offered on Fido, it
may be possible to get the fonctionality you desire without having same
phone number of 2 handsets.

This used to be possible with Rogers a long time ago (although it wasn't
really legal). There was a company in Montreal which basically cloned your
phone so that 2 phones would share the same number. I'm not sure exactly how
it worked. I was thinking about getting this done when it was first
"offered" because my handset was very weak and I had a "permanent" cellphone
attached in my car which had better signal strength but I never did. There
were also crooks who used this technique of "cloning" to make calls on your
account. From what I heard, when Rogers was not digital this was very easy
to do (cloning phones). The fact that your phone was on meant that someone
could read your information from your phone and duplicate it on their phone
with the proper equipment. They could then make phone calls on your account
when you in fact didn't lose your actual phone.