G'day,
Try clicking on "Powered by Hearme". Seemed to work for me first time.

I just got home after trying this on Alison's computer. Quickly set mine up & found Jon & Mark still there. We managed to sing about half a song each before getting cut off. There seems to be a time limit for each person to "talk". Either that or net congestion intervenes. Or something. It didn't seem possible to get right through a song.

Cheers,
Alan