if you dont want to download an app for the speed dial you could always make a shortcut of the people you want to call the most.
i currently utilize one of my screens as a speed dial screen.
go to the screen you want to make your speed dial screen
press anywhere on the screen and wait for the dialogue box to appear
you will see a "shortcut" option, choose and then select "direct dial"
you now have a speed dial shortcut
How do you cancel an individual contact from speed dial?
are you using a particular app for your speed dialing? if so, which one?
if you put a short cut on one of your home screens as a speed dial, then press and hold the short cut, when your droid vibrates, slide the short cut to the bottom of the screen where the trash can is. place short cut into trash can and it goes away.