First of all, welcome to China! Shanghai is a great city, and I'm there regularly from my perch up in Beijing. Just to answer some of your basic questions:
-VISA/MC, and in some cases AE, will work in most ATMs carrying the respective logos/trademarks of the creidt-card companies. For dedicated ATM-cards, some ATMs display a "Cirrus" logo or similar. If your bank in the US is part of this, your cars should still be useable.
-GSM and Skype works just as well here as anywhere else. There are two main companies selling mobile services, and the largest is China Mobile. They cover all of China and have roaming-agreements spanning the globe. One thing to be aware of though is that you can always send SMS out of China, but getting one into China is much harder. Having been here for 18 months, I have yet to receive an SMS from family and friends and always end up getting a frustrated call asking why I never reply to their SMSs.
-Internet banking should still work, subject to your bank not limiting the IP-addresses you can use when claiming to be you.
-Do's/Dont's much like anywhere else. Be polite, a smile will always solve more than fury, and with that in mind: Sharpen your elbows, as queing-cultire in China leaves a lot to be desired.
-When going out, if you are placed in a separate "VIP"-room in a bar together with a few ladies, leave immediately. People have been known to be charged astronomical amounts for two beers and a drink for the ladies. When protesting that they have only been drinking, they have been told that this is their own problem and not the bar's!

Enjoy the bustle of the place!
Enjoy Shanghai,