Using 'Data roaming' on unlocked iphone 3g. I am I going to be billed?

[kuru79]

Just purchased iphone 3g unlocked (used)
I am not sure how it was activated.

I have blackjack II (AT&T) given from my company.
It's under enterprise plan with 4mb data plan.

I got i-smart sim adapter. I put my AT&T sim (out of blackjack II)
into the 3g iphone, and it's working fine.

My problem is I have to turn on 'data roaming' to get edge or 3g.
(Didn't get 3g at my home, will have to check in downtown)

What will that look like on my billing statement. Of couse it goes to my company and they pay for it.
I am not using much of data plan (will limit it below 4mb).

Is there any APN setting that I have to do to aviod extra charges?

I meant to say "How am I going to be billed?"

[sziklassy]

ATT will eventually ask you to add a data plan for the iPhone. As far as the data roaming I am clueless.