Rumors are in the air that next generation iPhone 4G will come with video conferencing and iChat capabilities, 9to5mac has found strong evidence in iPhone 3.2 SDK for iPad pertaining to video conferencing and iChat options in upcoming iDevices.
TelephonyUI.framework in SDK shows some strings with "VideoChat" words, hence it clearly indicates that iPhone 4G and iPad both will have video capabilities.
Most probably video option will be available in both devices via a built-in app named iChat, as shown below VideoToolbox in SDK has a string with "iChat" term.
Next-gen iPhone is expected to be released at