I am talking pre-Cingular here. Former AT&T customers, also known as Cingular Blue customers.

Has anyone gotten their SIM to work in an iPhone? I could get Cingular SIMs to work but not blue Former AT&T SIMs, nor the white ones.

Short version:

Won't work. You can either commit to a new rate plan for 2 years (getting a new sim card, make sure of that) and use the hack, or just activate the god damned thing properly.

I'd suggest commiting to a new rate plan and getting a new crackberry or similar, then switch to iphone and sell the blackberry.

Note, there was at least one report (granted from an almost illiterate fool) of AT&T autodetecting the hacked iphone's presence and removing the foundation account number (discounts).