As far as I know, Skype on Android is exclusive to Verizon. Works on iPhone and iPod touch though. If you want her to be able to do VOIP, iPod Touch is probably your best option.

Kinda wandering off topic here, but I've found Facetime to be much better than Skype for low-bandwidth voip (and video). The caveat being that it only works with other Facetime enabled devices.

Also, I'm unfortunate enough to live in a country where Skype is blocked on the national level, but Facetime is not.