For a while now I have been using the wonderful with my MacBook Pro.  I would also like to share out a few tips that are not very obvious when dealing with other keyboards on Mac.

The Microsoft Natural 4000 Ergonomic Keyboard

1. Microsoft, amazingly enough, provides software that smoothly integrates with OS X, its Preferences, and even iTunes to allow your keyboard’ Play/Pause, Volume Up, Volume Down, Mute, and Calculator buttons, among others, to work as expected!
2. The Microsoft software that comes with this keyboard automitically rearranges the modifier keys (Ctrl, Alt, Option, Cmd, Windows) to have the same layout as your Mac’s normal keyboard.
3. The 4000 has a handy Document Zoom slider in the middle of the keyboard which works in a lot off applications such as Microsoft Word and Opera
4. Interestingly enough, the Microsoft 4000 includes an extra row aboved my beloved numpad: =, (, ), and Backspace. They are handy for Excel/spreadsheets and number crunching.

External Keyboards & Your Mac

1. Scroll Lock reduces screen brightness, and Pause/Break increases screen brightness.
2. If your keyboard has volume control (as does the 4000), the previous tip means that you don’t loose your MacBook Pro’s brightness and volume controls when using an external keyboard
3. Through the Preferences pane for Keyboard, Apple makes it very easy to switch Alt/Windows buttons to be in the same order as your Command/Option(alt) buttons. (The Microsoft software, however, makes this unnecessary; it automitically does so just for the external keyboard.)
4. Using an inexpensive, short dongle (converting plug) on PS/2 keyboards does not let you use the device when plugged into a USB port! This only works if the keyboard was designed to work that way, and in that case, it will come with its own dongle. More expensive ($16+) converters should work.
5. Keyboard layouts differ; you may want to double-check that the shape of things like the Enter button is the same as they are on your Mac. The Microsoft devices are perfectly compatible as far as I can tell.
6. Curiously, sometimes the Delete button (not Backspace) does not invoke a Delete command and you must still use Command-Backspace.
7. This is barely relevant, but Adobe Photoshop (on both Windows and OS X) assigns differnt actions to Return (a/k/a Enter) and (Numpad) Enter; (Numbpad) Enter "confirms changes" when editing type, whereas Return/Enter adds a new line of text.

Updated August 1, 2007.