I wish someone told me......

...how not to get a HUGE data roaming bill on my new iphone whilst abroad.

The reason I got a £900 (I still can't quite believe it!) O2 bill is all down to frickin mobile.me which I discovered downloads every 15mins for 24hrs a day!! This is how it 'magically' keeps all your stuff on the computer up to date with all your stuff on the iphone, this is why if you lose your iphone you can send it a message, change the pin code or erase it, because its constanlty downloading to it.
So if you too are having to get an £80 pr month 'bolt on' just so you can keep that lovely data roaming setting in the ON position this is how to avoid all that nonsense.

settings>mail,contacts,calenders
go into the fetch new data page and turn 'PUSH' off
turn fetch to MANUALLY also,
scroll down tap ADVANCED
tap all settings to MANUAL
go back to mail,contact,calenders and turn FETCH NEW DATA off

All this stops it constantly downloading without turning off data roaming whislt abroad, then you can choose when to download your emails by going into emails and tapping on the refresh button. Mine does it automatically the minute I go into 'mail'.
Of course the other solution is to turn off data roaming off whislt abroad but if you travel as much as I do that becomes a real pain, this way works better.

simples!