Verizon is
CDMA and doesn't use
SIM cards. Cingular is
GSM and DOES use
SIM cards. There are
CDMA RAZRs for Verizon and
GSM RAZRs for cingular, etc. But one technology will not work on the other's network. If you want a SLVR it is only
GSM and will only work with Tmobile, Cingular, and other
GSM provider, NOT Verizon.