While it was possible to use Skype already for quite sometime through other service aggregators such as Fring starting from March 31 on you can directly install a Skype app on your iPhone or IPod Touch.
I have tried the chatting function and it works very well, better in fact than the Fring version so that there is no need for me anymore to use Fring.
The Skype iPhone app has been downloaded 2 million times the first week which is an unbelievable number. The potential are more than 400 million Skype users of course and with that creates some real threat for the mobile operators it seems. Interestingly, these iPhone Skype users seem new users who have not been using it on their PC before so the Skype community keeps growing with this too. Last but not least they are coming out with with Skype for other mobile platforms so soon it will be around on all smartphones it seems.
I still have to use the voice function but will certainly do so on my next business trip. The cost savings are tempting no doubt even if you have to first find a Wifi connectivity. The mobile operators have to react now with some very attractive service bundles I think. To try to block them from their network is of course another protective measure but hardly a long lasting strategy. Providing attractive international voice, data roaming packages is the way to go I strongly believe.