Yes it has. And i think you should use the apple usb cable with an ipad but not all the cables fit.
Plug it in.
Your iPad came with a usb cord that attaches to your iPad with the big end and the other end (the one with the usb plug in) goes into your usb slot on your computer.
No
No apple does not put USB plugins in the iPads
You get the iPad its self, the USB charger with socket adaptor, you get the owners manual and two apple stickers.
Apple's iPad 2 comes with the basic essentials you will need to operate the iPad. Besides the iPad itself, also included is a USB cord that syncs and powers the device. Also, a power brick, which can be used with the USB cord to power the iPad direct from a wall outlet. This brick is also handy if your computer's USB port does not have enough power to charge the iPad. The iPad itself has it's own software already installed and is usually close to a full charge. The iPad's Smart Cover, which you frequently see in photos of the device is not included.
The USB Port on an iPad is for either charging, or syncing media (music, apps, etc.) to the device.
No,ipod and ipad are two very different types of technology where as the iphone does have a chance of charging with the ipad usb adapter.
iPads do have usb ports. You just have to buy an adapter
none
USB ports, unlikely. Mac OS X, no this is impossible as the iPad is not a Macintosh.
iPads cannot use USB modems.