The iPad really is a giant iPhone—so much so that if you want to get a laptop-like experience out of it, you'll need adapters to change the typical 30-pin connector into USB, SD, or AC power. Correction:
In addition to the keyboard attachment, there will also be dongles, attaching to the 30-pin dock connector, that give a USB port and SD card slot. In terms of charging, there's no built-in MagSafe connector or anything, so they'll also be shipping an iPod-to-AC cable as an optional extra. Correction: The 10W USB-to-AC cable will be included in the box, not an optional extra as I wrote earlier, in the heat of the battle (and Apple events are battles, at least for us).
The USB and SD adapters are billed as the "Camera Connection Kit," which may mean they're sold together and may also mean their features are limited to importing photos and videos. From Apple:
The Camera Connection Kit gives you two ways to import photos and videos from a digital camera. The Camera Connector lets you import your photos and videos to iPad using the camera's USB cable. Or you can use the SD Card Reader to import photos and videos directly from the camera's SD card.