On Thursday, Nimbuzz released a significant upgrade to its iPhone application including integration into SkypeOut and 10 SIP networks for cheap international phone calls over WiFi, plus an app to enable calls on an iPod Touch.

New features include the introduction of a dial pad and the ability to make VoIP calls to landlines and mobiles via Skype-Out. Nimbuzz provides the available Skype credit left on the dial pad when using Skype Out for phone calls to landlines and mobile phones. New VoIP call options are available through the company’s global affiliate SIP partners, including Gizmo5, Vyke, and SIPgate.

The networks are integrated into the interface to use Nimbuzz for cheap international calls to landlines and mobile phones over WiFi. A two week online banner campaign to promote iPhone SIP calling functionality will be conducted on partner sites Gizmo5, Vyke, and SIPgate.

In its press release, Nimbuzz also took the time to brag about adding one new user in less than 4 seconds, translating to over 20,000 new users a day; however, the company would not disclose the total number of users it has According to an October 2008 user survey, 95 percent of Numbuzzers would recommend the service to a friend. There are also signed manufacturer partnership agreements with RIM, Spice Mobiles, and Toshiba.