Back to basics.

How to make a conference call.
1. Find a conference call provider. You can pay per conference call (and get charged according to how many people call in, how long the call lasts, etc.) or purchase a flat rate conference call service, in which you have unlimited access to a conference bridge at a fixed monthly cost.
2. Some services will require you to buy hardware and/or add/switch long distance service, but there are prepaid conference call services that will allow you to use your landline telephone, mobile phone, or computer.
3. Consider if you want a toll free conference call service (ex: 1-800) number, or if you want participants to pay long distance charges when they call in.
4. Conference calls can also be used in conjunction with web conferences, so participants can view documents or presentations simultaneously while on the call.