You can use Spotlight if you have Tiger, or the superb
Quicksilver.
If you go to System Preferences/Keyboard & Mouse/Keyboard Shortcuts you will see a list of system wide keyboard shortcuts. I think the default shortcut to focus on the Dock is ctrl-F3, of course you can change it to something more convenient. You can then use the arrow and enter keys to navigate across the dock.
I'd go with Spotlight/Quicksilver though
🙂