Slashgear brings news that there is now a VoIP app in the Apple App Store for the iPhone (and iPod Touch) which allows IP calling over 3G networks.

The software, known as iCall allows for incoming call notification even when the application is not running.

This signals a lifting of the 3G VoIP calling restrictions which Apple imposed on iPhone apps.

Truphone who provide a SIP standard voice over IP calling system for mobile handsets of the Symbian S60 platform as well as some iPods and the iPhone have announced that they will now support Paypal payments for customers using iPods and iPhones.

While a number of debit and credit cards were already accepted, customers will now be able to use Paypal through their device to add land-line calling credit without the need to resort to using a web-browser equipped personal computer.

Sipgate, an established SIP Voice Over IP provider has announced a new software product for the Apple iPhone.

iPhone users will now be able to use a SIP application directly when connected to WiFi hotspots to make free or reduced cost calls over the internet.

This brings the iPhone in line with other WiFi enabled smartphone which have SIP functionality directly available.

Sipgate appear to be offering their free iPhone product via their USA, UK and Austrian websites although, if the software is truly SIP compliant, there shouldn’t be any geographic limitations to its use.

iCall has a closed beta of their system for the iPhone in work.

iCall allows you to route your incoming cellular network calls to your iPhone via VoIP when you are connected to a WiFi hotspot. You can also send and receive VoIP calls over WiFi.

Watch the demonstration video for more information.

Blonde 2.0 for Mashables.com brings us news that mobile p2p VoIP provider fring has released it’s API for third party developers.

This will enable others to develop new applications and add-ons for the fring platform.

The fring platform supports mobile devices such as the Symbian Series 60, Sony Ericsson UIQ, Windows Mobile 5 & 6 and the iPhone.

As a network, fring also integrates with Skype, AIM, Twitter, Google Talk and the industry standard SIP protocol.