Does the new iPhone 4S have a SIM Card easily accessible/removable?
I've asked each carrier ATT and Verizon, as well as the Apple store - nobody seems to have any answers.
Yup! The 4S has a microSIM slot right on the side, just as the AT&T iPhone 4 did.
Does this mean if I go to another GSM country, I could have their SIM card installed for in that country local calls and Internet?
It needs to be unlocked for you to use in other countries. If I remember, Sprint and/or Verizon will unlock for you after a certain time with them.