How can you tell if your Nexus S is CDMA? I am trying to flash ICS onto my Samsung Nexus S, but I'm getting the error E:failed to verify whole-file signature.  Really irritating since this is described by many to work.

I'm guessing that my phone is the CDMA version, but how do you know for sure?
CDMA phones don't use SIM cards, that's the most obvious way to tell.  (Some world phones are both CDMA and have GSM hardware and SIM cards, but that's not relevant here).  Most carriers are only one or the other so your carrier should be a good indication as well.