A new forum post at ModMyi.com details how to use an existing AT&T SIM card in the recently-released iPad 3G. In order to make the card work, people must trace the shape of a micro SIM card onto the full-sized one, and cut it out with an X-Acto knife. The result should work in the iPad's micro SIM slot after changing the device's APN setting to "phone." Alternately, the carrier testing mode can be used in iTunes to enter a custom IPCC file. Melech518, the user who posted the article, suggests using Stealth's ATT_US_STEALTH.ipcc, and has allegedly confirmed that the m
