I looked at Cosmote's and Wind's new WAP offers when I was in the Ionian in October. Both said that the Poseidon weather site was part of their portal - so maybe excluded from the 40Mb. Can you tell whether it is?
Poseidon
I also talked to a guy in a Vodafone shop in Vathi on Kefalonia. I told him why we (sailors) needed data access on prepaid cards. He said that Voda might be doing 'something' on prepaid 'next year'.
He was probably just being polite - or stringing me along - but it might be worth enquiring in a Voda shop while in Athens.
Dave (in the UK - returning to Greece in April)