I don't think they are too concerned about sending it our way, I saw an article just today that they have updated the iPhone version, but still nothing on the BlackBerry version.
We can't use skype on Vodafone (and other UK networks apart from 3) because they start charging us for data, i.e. If they detect skype, then it voids our internet plan
Its fairly obvious why they do that; cheaper international calls via skype, so vodafone will have to compete them - but then vodafone lose money on their excessive international charges, etc.
So instead, I take my iPod touch (and microphone earphones) with me, and use that instead (over the wifi). They lose money either way. But I spend more time using a device they don't have a stake in...
I presume you can use international phone cards over a mobile if you're calling a freephone number to access them...?