WordNet (r) 3.0 (2006):

usher in
    v 1: be a precursor of; "The fall of the Berlin Wall ushered in
         the post-Cold War period" [syn: inaugurate, usher in,
         introduce]

Moby Thesaurus II by Grady Ward, 1.0:

58 Moby Thesaurus words for "usher in":
   announce, antecede, antedate, anticipate, be before, be early,
   blaze the trail, break the trail, bring up, broach, christen,
   come before, come first, establish, float, forerun, found, front,
   go ahead of, go before, go in advance, guide, have priority, head,
   head the table, head up, herald, inaugurate, induct, initiate,
   install, institute, introduce, kick off, launch, lead, lead off,
   lift up, originate, outrank, pioneer, precede, precurse, predate,
   preexist, proclaim, raise, rank, rate, ring in, set agoing,
   set on foot, set up, stand first, start going, start up,
   take precedence, turn on