[Edtech1]

I used to be able to take my iphone4 sim with it's unlimited data plan and put it into my iPad and change a few APN settings and the iPad 3G would happily hop onto the ATT 3G network and I could surf and access data services for free without a separate data plan for the iPad.

However, after upgrading the iPad to iOS 4.2.1, it appears that I have no more access to the APN settings which used to be found under the cellular settings preference. Does anyone know how to get back the ability to input APN settings under IOS 4.2.1 on an iPad? Or has Apple successfully closed that loophole?

[Cold Warrior]

It's probably possible to do it with a mobileconfig file. You could build your own using Apple's iPhone configuration utility, then email it to yourself (or host it on a web page, even on a LAN web page) to load the settings. iOS will obey.

Or try this site, which lets you build a mobileconfig file given APN, user name, and password.
About | iPhone APN Changer

edit: It also has an at&t preset, which may help.

[Cold Warrior]

p.s., I just did something similar for prepaid H2O Wireless data on an old 3GS.