>Does anyone know of a company that supports VoIP conference calls as a part
>of their service offerings?
Voicepulse does. See www.voicepulse.com. Their conference rooms
require no reservations and have POTS and 800 phone numbers so off-net
people can call in.
> Or is it possible for us as a company to purchase a server
> appliance that can act as a conference server for VoIP calls.
If you have a fast Internet connection (like a T1) and your remote
employees have broadband connections, it might make sense to give them
VoIP phones and install an Asterisk PBX at your site to handle both
the conference calls and other employee-to-employee traffic. For
off-net users you can either get interface cards for the PBX to hook
to local phone lines, or contract with a voip vendor like Voicepulse
or Iconnecthere to provide voip-POTS gateway service.