WindowPrompt brings windows to you and you to windows. That is to say, it pops up a prompt with window names, in case you forgot where you left your XChat.

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

 import XMonad.Prompt
 import XMonad.Prompt.Window

and in the keys definition:

 , ((modMask x .|. shiftMask, xK_g     ), windowPromptGoto  defaultXPConfig)
 , ((modMask x .|. shiftMask, xK_b     ), windowPromptBring defaultXPConfig)

For detailed instruction on editing the key binding see XMonad.Doc.Extending#Editing_key_bindings.