WordNet (r) 3.0 (2006):

preachy
    adj 1: inclined to or marked by tedious moralization

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "preachy":
   admonitory, advisory, cautionary, consultative, consultatory,
   didactic, directive, exhortative, exhortatory, expostulative,
   expostulatory, hortative, hortatory, instructive, monitorial,
   monitory, moral, moralistic, moralizing, recommendatory,
   remonstrant, remonstrative, remonstratory, sententious,
   sermonizing, teachy, warning