The keyboard shortcut for Spotlight on the Leopard Mac is Command + Space bar. But I use an IDE that has Control + Space bar as the shortcut for the auto-completion functionality. Since I use my IDE a lot more than I use spotlight, I wanted to change the keyboard shortcut for it. Here's the steps.

- Go to System Preferences (you can find this in the Apple menu)

- Select Keyboard & Mouse

- Select the Keyboard Shortcuts tab

- Scroll down to the "Show Spotlight search field" entry in the Spotlight section

- Double-click on the existing shortcut

- Hit the keystrokes that you want to be the new shortcut

That's it. Once you do this the keyboard shortcut for Spotlight will be changed.