Please excuse if this has already been discussed, but it didn't show in any search results. I'm a longtime Verizon Wireless customer (since it was BellAtlantic--Nynex Mobile). I just learned that my CDMA iPhone 4S has a microSIM card. Huh? A SIM card in a CDMA phone?! Does a Verizon iPhone 4S also have GSM capability, specifically quadband GSM capability? Can I have Verizon unlock it, buy a nonU.S. microSIM, and use the phone overseas in GSM countries?
I understand CDMA vs. GSM, etc. and have a "classic" unlocked quadband Nokia GSM that I currently use for foreign travel.
Many thanks in advance!

iPhone 4S is CDMA and GSM capable. If you purchased the phone from Verizon though they may have locked the GSM functionality.

Yes, the 4S is dual CDMA/GSM. In the US, it will only ever work in CDMA mode. Overseas it will roam onto GSM networks, though it will prefer a foreign CDMA network over a GSM network if one is available (you can turn this off in Settings).

It's by default locked to only take Verizon SIMs. You can call Verizon and they will unlock it if you've been a customer in good standing for at least 60 days. Call Verizon Global Services at 800-711-8300 and ask for a SIM Unlock. If the rep is confused, explain that you want to use local, foreign SIMs in your phone when traveling outside the USA.

In order to apply the unlock, you will have to put in a foreign SIM when your phone has access to a wifi network. ONce the SIM is in, your phone will lead you through the activation process and unlock itself.

Note that the Verizon SIM unlock will only work for SIMs not based in the USA. You can use a T-Mobile Germany SIM but not a T-Mobile USA SIM, for example.

Now in Cambodia, using my vz 4s with local prepaid, 3G access

OMG, I am getting old, and rude! (Heh, I went to college in the 70's and killed a lot of brain cells.) I totally forgot to express my thanks to you all for your replies. A very late but sincere thank you!

Dead brain cells: did you ever get yours unlocked and use it overseas?

Not exactly. If your 4S is unlocked, and you are so inclined, a foreign country SIM would work here. I've tried it.

Yes, yes. Oops.

Actually, for some reason the foreign sim will override the Verizon CDMA and be the preferred 3G. One has to either take the sim out or go to settings each time the phone is turned back on.