Guys -
I need your technical advice.

My parents are getting married again (pearl anniversary) this coming March. And we have some relatives outside the country that can't attend the wedding.
Now they are all requesting to have the affair broadcast in live via internet. Offcourse the whole affair would last for about 4-5 hours and they would like witness all of that.
There are about 20 of them coming from different places (US, China, Singapore, France, Italy etc etc).

Now I'm looking for video streaming softwafe that i can use for this purpose. I've been using Yahoo Messenger Video Conferencing for limited participants the max i got is 5.

Do you think the YM video live feed can do the works or is there any limitation. Can you suggest other proven video streaming software available on-line for free.

Thank you very much for all your help in advance.