A website called MyVoIPProvider has been set up to compare prices for calls between PCs and the PSTN. The service ranks the top 100 providers by price. It also has a search engine which provides ranking for a particular country. Hop255 loaded Australia and the site produced VoIPCheap as the least expensive service. Unfortunately the ranking is only as good as the data and in this case 0.005 pounds (US$ 0.008) per minute had been entered instead of the actual price 0.05 pounds (US$0.08). This error led to VoIP Cheap being ranked first instead of 153. Ouch!
For the record NetAppel should have ranked first (assuming the other data are correct).
A directory of VoIP providers by county is a useful feature.