If you want to make ‘conference calls’ (calls to several people at once) you can use FreeConference.com to arrange them – but the free version uses a US non-freephone telephone number so you and your fellow freeconference users will probably still have to pay long distance charges.
Here in the UK, BT is selling “Buzz In”:http://www.bt.com/buzz-in/ which is quite a sophisticated conference calling system aimed at domestic rather than business use (doubtless to keep their business conferencing margins high!) but each participant pays 10p a minute – with long distance rates being what they are it would probably be cheaper for everyone just to call America and use FreeConference instead.
*Update:* “Voicemeeting”:http://www.voicemeeting.co.uk/ – another UK company which I just discovered – appears to work in a similar way but costs 5p per minute.
Does anyone know how to do conference calling using free Internet telephony? Of course you could always use the “free calls to the US”:http://blog.org/archives/cat_useful_web_resources.html#000967 that appear still to be available (without fanfare) via the VOIP software at “Free World Dialup”:http://www.freeworldialup.com/ but that may not last forever and it’s not a particularly elegant solution.