Users of the recently launched iPod Touch can now make VoIP telephone calls with their devices via wireless networks.

The so-called touchmods crew has released a beta version of what it says is "the world's first free SIP-VoIP application for the iPod Touch," though it acknowledges that there are some drawbacks associated with using the media players as VoIP phones.

Crucially the iPod Touch lacks a microphone, but the software developers said users can get around this hardware drawback by building their own microphone which can be attached to the dock connector - the instructions for which have been released.

Alternatively, and perhaps preferably for most everyday users, the team is also planning to commercially release a bespoke iPod Touch microphone which will retail for under €30 euros (£22).

Beta testing results show that the software is compatible with a range of VoIP providers as well as the popular Asterisk open-source IP PABX, but analysts caution that installing the software requires users to "jailbreak" their devices.

Despite being relatively straightforward and hazard-free, any unit that undergoes the modification - analogous to unlocking a network-specific mobile phone - immediately has its warranty voided.