VOIP in i-phone:
You can use VOIP in iphone with the recent changes of apple lifting voip apps restrictions.
Here is the list of some.
iCall
iCall for the iPhone is a revolutionary new product that lets you make and receive free or low-cost phone calls anywhere you have a WiFi Internet connection.
Fring
Fring is now available on the App Store for all versions of uPhone and iPod touch. All you need to do is download fring on the App Store and within minutes you can make free calls with other fringsters™ or via fring using Skype, Skype-out or any SIP providers you choose.
Acrobits
Acrobits Softphone is the leading SIP VoIP phone for iPhone. Use your iPhone to make calls over Internet from any place which has a wi-fi signal at very affordable rates.
Line2
Line2 adds a second line with voicemail to your iPhone. Place and receive calls from either number. Each has its own voicemail, call history, and contacts.
Nimbuzz
Nimbuzz have just released an iPhone version of Nimbuzz to bridge the 3G VoIP gap. Plus it also can turn the iPod Touch into an iPhone.
