You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Layout.Tabbed

Then edit your layoutHook by adding the Tabbed layout:

 myLayouts = simpleTabbed ||| Full ||| etc..

or, if you want a specific theme for you tabbed layout:

 myLayouts = tabbed shrinkText defaultTheme ||| Full ||| etc..

and then:

 main = xmonad defaultConfig { layoutHook = myLayouts }

For more detailed instructions on editing the layoutHook see:

XMonad.Doc.Extending#Editing_the_layout_hook

You can also edit the default configuration options.

 myTabConfig = defaultTheme { inactiveBorderColor = "#FF0000"
                                   , activeTextColor = "#00FF00"}

and

 mylayout = tabbed shrinkText myTabConfig ||| Full ||| etc..

A tabbed layout with the default xmonad Theme. Here's a screen shot:

http://code.haskell.org/~arossato/xmonadShots/simpleTabbed.png

This is a minimal working configuration:

 import XMonad
 import XMonad.Layout.DecorationMadness
 main = xmonad defaultConfig { layoutHook = simpleTabbed }