Daniel Finkelstein has a column in today's Times, where he complains about such words as pre-booked and pre-ordered, which he feels are tautologous. Both words are in the OED. I've noticed signs in bookshops saying 'Pre-order the new Dan Brown book today', so pre-order seems to relate to something which hasn't been produced yet.
As one of the column's commentators notes, the word pre-drink, is most definitely tautologous. It isn't in the dictionary, but gets plenty of hits on Google. Pre-drink means, well, 'to drink', and in particular to have a drink at home before going out for a drink.
Pre- originally appeared on words of French or Latin origin. It is the Latin equivalent of the Old English, or Teutonic fore-. Pre- began to be attached to English words (eg preclose) only in the late Middle English period. These days it almost always means 'before' (relating to time or the order of succession) although it very occasionally has the sense of 'intensive' or 'surpassing' eg prepious, prepleasing, pre-epic, pre-Luciferian.