Yes, I have this set up for my family in Turkey and it works very well. You need an 220 volt adapter though and a broadband connection with decent upload. If you search the forums, ooma moderators once posted there are hundreds of oomas that connect from abroad.
If you have ooma core, you can get this adapter which works for me (ooma telo uses a different DC voltage):http://www.apexcctv.com/p-376-12v-dc-power-supply-1500ma-regulated.aspx
You'll also need a grounded adapter plug based on the country you are taking it to.