Where's the 8pen Preview Popup?
8pen has now answered this at their official support site:


  You're right, in the early version of the 8pen from November 2010, we
  included a popup window. It's now removed, but we are considering
  putting it back again, as you are not the only one requesting this
  feature. 
  
  By the way, are you aware of the game "8pen Wordcup", available for
  free on the Market (http://goo.gl/Qvpiw)? That should get you quickly
  up and running with the new layout, so you won't need to be looking
  for letters all the time.