Here’s the cheapest way I could find to make a conference call that uses your computer to set up a conference call between any normal landline phones.

1. Set up a free account at http://www.freeconferencecall.com

They will give you some details like:

Free Conference Call
Conference Dial-in Number: (616) 597-8000
Host Access Code: 123456*
Participant Access Code: 123456#

To make the conference call, all you need to do is ring the number 1 616 597 8000 from a normal phone and when it asks you, enter the Access Code on the phone keypad. (eg 123456*)
Then every other person who want’s to be on the conference needs to ring the same number and enter the same Code (123456*)

The problem is the number us a USA number, so it’s going to cost a lot.

To get the call to the USA cheap, I signed up with pennytell, then go to their Web Callback page.
Enter in your phone number, then the conference call number, like this:

This will connect your number to the conference call number.

You can repeat this for every person you want to connect – replace your number with their number – and it will ring them and connect them into to the conference call. (Make sure you give them the access code (eg 123456*) and warn them what’s happening!

The people you call into the conference will not have to pay, your pennytel account will be charged at 3.2 cents per minute per caller.

BROADBAND INTERNET
You need broadband with at least 128Kbps UPLINK speed, but to work well you really need 256.

Eg 512/128 is too SLOW.

1500/256 is GOOD.

1500/512 is EXCELLENT.

YOU NEED A PHONE TO INTERNET ADAPTER, called an ATA. (Otherwise You’ll have to have your computer turned on all the time and use a program like skype)
The ATA plugs into your network, and then your normal phone into it.
You can spend lots of time looking for a good one, but the SPA3102 I use is pretty good, it plugs into the phone line as well so that if your internet is not working (eg in a blackout) you can still call out via your normal phone line.

YOU NEED A VOIP PROVIDER
Engin is very popular, but like telstra, popular doesn’t mean the best deal.
I tried 4 or 5 for a month, and now I use pennytell, 2c per minute calls, 13c per minute to mobiles.
Also you need to pick a good codec, this is a bit tricky. Make sure whoever you buy the SPA3102 from can help you set it up.

I’ve found G726-32 is good.

G711 may be better quality theoretically but breaks up too much when the line speed drops.
G723a. I think may be good too.
I read this somewhere…
“The most commonly used mode G726-32 , since this is half the rate of G.711, thus increasing the usable network capacity by 50%. It is primarily used on international trunks in the phone network. It also is the standard codec used in DECT wireless phone systems.”