Ok, just to add my tuppence worth. Firstly, I am onVirgin Pay-As-You-Go. I've only ever had one mobile on a contract, and never again because I think the charges are a rip off, but anyway thats another story.
What I usually do is buy a Sim Card for one of the Mobile networks in the country I am visiting. Basically I am on Virgin, but I travel to Spain a lot so I have bought a VodafoneES Sim Card. I usually find that this works out much cheaper when sending texts back to the UK. For example, Virgin charge .35p per text sent back here. But my VodafoneES simcard means I only pay less than half that amount per text.
Voice Calls also work out much cheaper. I have also been advised by the people that send me texts while I am abroad that they are not charged any extra than their standard Network rates.
I think this is because whilst you are abroad, if you use your own mobile then the calls, texts have to be routed to the UK, then back to the country you are in and then back to the UK again. Or so I have been informed.
However, if you use a local Network, then your texts are simply sent directly back home without being routing twice.
The only drawback with VodafoneES is that you have to keep your Sim Card topped up, because if you don't then it will be disconnected after nine months.
But buying credit with VodafoneES is very simple. You can buy a top up card for €15, but a small part of this will aotomatically be deducted in tax, so your mobile will be credited with just a little over €12.
It is still well worth considering buying a local Sim card though. Just make sure your own handset is UNLOCKED, and not locked into your existing Network Provider.
Failing which, make sure you have your voicemail activated and do NOT accept incoming calls whilst you are overseas as the costs can be extremely expensive not only for the person making the call, but also for the person receiving it.
Also another little tip is this. Again this is aimed at those of you on the Virgin Network. If you choose to text or call home whilst you are abroad, make a note of the time you sent the text. keep an eye on how many pages of text you are sending and make a note of the destination number. The go to a local Internet Cafe or wherever you can access the Internet. LOg on the Virgin wbsite and register your account if you have not already doen so, and then you can keep an eye on your account and what you are being charged. I'm not suggesting you spend all your time on holiday checking your phone bill, but just say one each week you atre away.
I did this because Virgin made a mistake with my account on one overseas trip and charged me three times for each single text I sent. I called them and explained their errors, but they would not budge. So I emailed them and complained and threatened to take my custome elsewhere. Within 24 hours they had credited my account with the costs of the texts I had been challenging.
As I say, this is how it works out with PayAsYouGo. I can't comment on Contract as I've only ever had one contract mobile and I don't agree with their hidden charges.....but as I say thats not for discussion on these boards, accept to say be on your guard, as you may get a bill you cannot afford to pay. I did, and thats why I switched back to PasAsYouGo.