Data plan help needed for legally unlocked iphone

[hyperbolical]

dear all, i hope someone can help me.
i bought a legally unlocked iphone in italy, it works fine, i travel internationally alot and often live overseas so a at&t phone did not make sense.
the problem is that here in the states, when i use my at&t sim card, i am getting enormous data charges. i tried a data plan for my at&t pay-as-you-go sim card but the 5mb plan gets used up in a day or two, yet i do not use the internet much except for email, i go to yahoo page for my email, could this be the problem? i can't figure out how to make it just use wifi which is what i do when the sim card isn't in. i just got this so still learning.
i read on other forums i need to turn EDGE off but not possible with firmware 2.2.
Does it matter if i turn off data roaming or fetch?
if someone can help me configure this properly i would be very grateful. thanks alot
c

 

[polarbreeze]

Does it matter if I turn off data roaming or fetch?

You say you're not using the internet much but if you're going to Yahoo to check your email, then you are in fact using the internet a lot and it's not surprising that you're using up 5MB pretty quickly. You'd be better off using Apple's mail app instead and turning off "push" so that you can manually sync your email only at WiFi locations and avoid using the cell network.

Also your other apps might be using the cell network, it doesn't take much to use up 5MB - do you ever use the GPS for example?

Regarding data roaming, if it's an AT&T SIM in an AT&T area you shouldn't be roaming so turning off data roaming shouldn't be necessary - but you could try it as a diagnostic and see if it makes a difference.

 

[benflick]

You may need to Jailbreak and install BossPrefs from Cydia. That will give you the option to turn off edge.