Overseas, things are heating up in the world of mobile VoIP. Two related announcements indicate that the segment is about to undergo some serious competition. Skype has confirmed release of its software for Apple’s iPhone device. Additionally, TruPhone, a London-based mobile VoIP startup is expected to announce new service offerings.

In what is largely seen as a preemptive move against Skype’s release for the iPhone, TruPhone is expected to introduce two new calling options:

… a flat-rate plan (TruUnlimited for Landlines) that would allow its customers unlimited calls to landlines in 38 countries for just over $14 a month. In some countries — the U.S., Canada, China and Hong Kong, for example — the plan would also allow unlimited calls to mobile phones as well. Truphone is also offering another plan (TruUnlimited for Mobiles) that would allow unlimited calls to mobiles and landlines in 64 countries for about $35 a month.

According to GigaOm, the Skype mobile application will utilize WiFi networks and calls to landlines will cost 2.1 cents a minute.  So, Skype calls will not be placed over AT&T’s data network, but through the iPhone device’s WIFI connection.

So much for all the vaunted talk about the power and capability of 3G networks. The iPhone Skype application’s use of WiFi indicates that 3G networks in North America could not deal with the additional pressure of increased VoIP traffic.

The iPhone’s popularity has been a crucial part of TruPhone’s success.  With Skype now entering the picture, TruPhone and other competitors have begun lowering prices to maintain market share.  Falling prices can only entice more users to consider using mobile VoIP services.