I think the point that the first poster was highlighting was for those who use their mobiles abroad to text back to the UK. I presume that ASFKAP is talking about having nipping in to an internet cafe or such like to send a text message from there? Alternatively, using the web browser on the phone whilst abroad would cost significantly more than the original text message anyway.
I've just been looking in to this as my contract is due for renewel. Tesco's mobile apparantley do a promotion which on the face of it seems a little steep but actually could prove useful if 'take_that' is using a lot of internet use abroad.
The deal is for a top of the range Iphone 32gb which will cost an additional £50 but the tariff allows unlimited calls and texts within the UK only, along with unlimited internet use in any country where you can get 3g coverage. This comes at the price of £60/month and you are locked in for 24 months.
As mentioned previously this although reasonably appearing reasonably expensive could prove significantly less so if you were a regular 'web guru' or had a small internet business which you need to keep a check on.
Unfortunately, I can't add any more light on the subject of a tariff that allows free texts from abraod to the UK as O2 used to do.
Perhaps someone else will know of another similar scheme?