"Skype may be on iPhone and iPod Touch"

Barton Hudson : " speculated that this was going to happen a week ago, but now it is clearly better than speculation. The new iPhone/iPod SDK has been officially announced, and it will be released to developers in June. There will be nothing in it to prevent Skype, with very little alteration to its core library, from running all its features over the WIFI network that is built into both iPhone and its little brother the iPod Touch. You won't be able to run VOIP/Skype on the iPhone's cellular network, but that was not something that could be done anyway." source.