When the iPhone first was announced, "visual voicemail" was a key selling feature, but when it eventually reached Australia, not a single operator implemented the feature. Now Vodafone has belatedly added the option to its iPhone bundle.
Vodafone iPhone users need to ensure they're running the latest iPhone software for visual voicemail to work, but after that it's pretty self-explanatory. The idea of visual voicemail is that you can see details of each voicemail message independently (including who left it if caller detection is working), and listen to them in any order.
One restriction: this only works in areas with decent data coverage; if you end up in an area where GPRS isn't working (it happens), you'll revert to normal voicemail. It'll be interesting to see if other local providers follow Vodafone's lead. Thanks Homer!