Conference Calling Companies

I Searched on google for conference calling companies but did not find much. But later on i found some details that i wish to share among ya'll.

Conference Call - A conference call is a telephone call in which the calling party wishes to have more than one called party listen in to the audio portion of the call. The conference calls may be designed to allow the called party to participate during the call, or the call may be set up so that the called party merely listens into the call and cannot speak. It is often referred to as an ATC (Audio Tele-Conference).
I thought all companies provide conference calling facility. But still, I made some searches for Conference Calling Companies and found some companies.

Conference Calling Companies -

Live Office Teleconferencing
Global Conference
ConferenceCall.com
Teleconference.com
Budget Conferencing
Unlimited Conferencing
Vonage
VoIP.com
Lingo
Genesys
ConferencePlus
ReadyComm Conferencing
HearMe
iVisit
VideoConference.com