You can use this module by importing it into your ~/.xmonad/xmonad.hs file:

 import XMonad.Layout.PerWorkspace

and modifying your layoutHook as follows (for example):

 layoutHook = onWorkspace "foo" l1 $  -- layout l1 will be used on workspace "foo".
              onWorkspaces ["bar","6"] l2 $  -- layout l2 will be used on workspaces "bar" and "6".
              l3                      -- layout l3 will be used on all other workspaces.

Note that l1, l2, and l3 can be arbitrarily complicated layouts, e.g. (Full ||| smartBorders $ tabbed shrinkText defaultTConf ||| ...)

In another scenario, suppose you wanted to have layouts A, B, and C available on all workspaces, except that on workspace foo you want layout D instead of C. You could do that as follows:

 layoutHook = A ||| B ||| onWorkspace "foo" D C

NOTE that this module does not (yet) work in conjunction with multiple screens. =(