http://www.skype.com/download/skype/windowsmobile
download skype for pocket pc.
she will need to use her credit card before she leaves to buy, 'skype out' minutes. 10-20 bucks is about all. that way she can make outgoing calls to any phone in the world. she wont be able to recieve a call though. 'skype in' is expensive, like 20 bucks a month. skype out is a 1 time thing and u can buy more minutes as u run low. now if u have the pc version of skype running on ur computer at home, and she has the pocket pc version on her phone, she can call for free and doesnt need to buy 'skype out' minutes. skype to skype calls are free. just need a username. skype to phone calls use minutes. to give u an idea i called austrailia from USA, the call was like 15-20 mintes and i think it cost me a total of 35 cents. omni is new so test skype out on it before she goes. also it only works thru the speakerphone, so have her take a blue tooth or better yet a plug-in headset. one probibly came with her phone. goodluck.
when she calls she need to dial +1 then the 10-digit number, +1 is the usa country code.