I have heard something called PAYG - which allows you to keep the same number wherever you go. But pls check the cost involved in such contracts.. they might be heavily priced!!
In my opinion, skype is the best opion for making calls from abroad.
Yes, no doubt it will be much better looking for skype so that later it will be more beneficial in making necessary calls. I have seen many people looking for further updates so that it will not be a problem making calls and thus setting up communication further.