Skype plans to begin offering a mobile VoIP client for iPhone through the iTunes App Store starting tomorrow. The New York times reports a BlackBerry version is due out in May.
The mobile clients will let users make free calls to other Skype users or low cost long distance and international calls to other phones. iPhone users will only be able to use Skype when connected to a WiFi hotspot, which prevents users from connecting to the AT&T network and skirting AT&T international fees by making calls over Skype.
In addition to making phone calls, the mobile client allows users to send instant messages, make conference calls, and snap profile photos using the iPhone's camera. You can find a series of screenshots of the iPhone app at Skype Journal.
Of course skpe has been on windows mobile forever