The battle between European network operators to secure the rights to distribute the iPhone continues, with Vodafone once again described as the front-runner.

Reports this week suggest Apple and Vodafone remain in talks to bring the must-have device to Europe, but final agreement hinges on volume guarantees and subsidies.

Unlike Cingular/AT&T, Vodafone wants to be able to subsidize the phone and doesn't want Apple to maintain control of iPhone sale prices.

It's known that seven million UK mobile users may be tempted to switch to the device when it ships, but more conservative estimates suggest six million units of the device will sell in the first three years.

Vodafone offers a strong 3G network and sells its own range of 3G modems for Macs, though the iPhone as introduced in the US lacks 3G support.