I learned a couple of interesting tips last night from Tom Hesser on the PowerPage Podcast about the iPad when used with a keyboard:
When your pair Apple's mini Bluetooth keyboard ($69) with the iPad it completely overrides the on-screen/virtual keyboard. This is a minor annoyance when you leave the keyboard in another room and forget to turn it off first. To get the iPad keyboard back, press the Eject key on the BT keyboard, or simply turn it off with the power button.
The brightness play/pause, skip and volume function keys on the BT keyboard work as expected with the iPad. The Expose and Dashboard keys don't work with the iPad.
You can use the shift and arrow keys to select text.
Command X, C, V works for cut, copy, and paste.
The iPad keyboard dock ($69, above) has a few additional features to those gained with the BT keyboard, specifically:
The top row of keys on the keyboard dock are devoid of function numbers, and, if you look down in the lower-left corner of the keyboard, the function key is gone as well. It was replaced with wider control, option and command keys.
The first row of keys are dedicated to home, spotlight, brightness down, brightness up, photo slideshow, toggle the on-screen keyboard. After a blank key are the usual music (play/pause/skip) and volume controls. The eject key is replaced with a lock key that instantly locks the iPad.
TiPB.com also notes another nice feature of both the BT keyboard and the keyboard dock: pressing any key immediately turns the iPad on without having to slide-to-unlock.