UPDATE: this rumor has been proven false by iLounge as of 12/14/2007.
According to a breaking story at CNet site iPhone Atlas, the unlocked iPhones that are available via France's Orange network are not actually fully unlocked. Apparently the "unlocked" iPhones will only work with SIM cards from other French carriers -- one could not, for example, put a T-Mobile, AT&T, or Rogers SIM card in it; only with a carrier that operates in France.
So yeah, there's some crud news. I wonder if we'll ever be able to safely unlock the device. I'd like to be able to give this iPhone to my wife someday, but she's not with AT&T.