“Does the iPad have a USB port where I can connect my digital camera or camcorder to transfer movies?”
The only ports included on an iPad are the standard Apple dock connector and a headphone jack. If you want to connect anything else you have to buy additional hardware. Fortunately one of the the add-ons available from Apple is a USB port.
To add a USB port to your iPad, by way of the dock connector, you need to purchase the iPad Camera Connection Kit. The kit includes two dock connectors. One connector has a slot for connecting USB devices to your iPad. The second connector is for SD memory cards. Most digital cameras can be connected using the USB connector. As of this writing, I haven’t found a video format supported by either dock connector, but hopefully that’s something Apple will address in the future. iPad apps can read memory cards connected to the iPad Camera Connection Kit, so there’s a good chance someone will offer a video reader soon.