|Technically no but to get the best out
of VoIP then yes you do.
services will work on dial up modem connections as low as 33k you will
experience a poorer quality of service when compared to broadband. The
chances are that if you are still using a 33k modem then the rest of your
PC is just as antiquated so VoIP won't work anyway. If you must (or simply
havn't got a choice) then use a 56k modem (cheap as chips nowadays)
VoIP will work on cable and ADSL broadband