I just got a reaction from 02:
"The various GPRS Call Data Records (CDRs) generated for each session are consolidated into a single daily total. The daily total is then rounded up or down to the nearest Kbyte, based on the following rules:
Daily usage: 0 to 512 bytes: total sent for pricing is rounded down to 0 Kbytes. Daily usage: 513 to 1024 Kbytes: total sent for pricing is rounded up to 1 Kbyte. So usage of less than 512 bytes in a day will not be priced. Usage of 0.5 to 1.5 Kbytes in a day will be rounded to 1 Kbyte. Usage of 1.5 to 2.5 Kbytes will be rounded to 2 Kbytes, etc."
And they offer data roaming in Chili, Nicaragua, Jamaica, USA, New Zealand, Australia, Indonesia, Singapore, Malaysia, Thailand and Vietnam. So that's covered!
No data coverage in Bolivia, Peru, Panama, Costa Rica, Fiji, Vanuatu, Laos, Cambodia, Myanmar and Nepal though
Laos had pretty cool sms rates! to 10-15 countries its free, and to all other countries they charge 0.15 kip, which means you can send about 8300 sms for 1 eurocent

Active sims NL Telfort, KPN, Vodafone, TrendCall, T-Mobile
DE Simyo
CH M-Budget
PE Claro
INT Air Baltic Card, GeoSim
Non-active sims NL Qick, Easymobile, Tele2, Simyo, Rabomobiel, Vectone, UPC, GT Mobile, Orange, Hema, Lycamobile, Carey
TZ Celtel
Malawi Celtel
Zambia Celtel
SA MTN, Vodacom
INT UM, UM+, Go Global Sim, Max Roam, 09 Sim