The Collaborative International Dictionary of English v.0.48:

Alphabetize \Al"pha*bet*ize\, v. t.
   1. To arrange alphabetically; as, to alphabetize a list of
      words.
      [1913 Webster]

   2. To furnish with an alphabet.
      [1913 Webster]

WordNet (r) 3.0 (2006):

alphabetize
    v 1: arrange in alphabetical order; "Alphabetize the list" [syn:
         alphabetize, alphabetise]
    2: provide with an alphabet; "Cyril and Method alphabetized the
       Slavic languages"

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "alphabetize":
   alphabet, analyze, arrange, assort, break down, capitalize,
   catalog, categorize, character, class, classify, codify, digest,
   divide, file, grade, group, index, initial, inscribe, letter, list,
   mark, order, pigeonhole, place, range, rank, rate, sign, sort,
   subdivide, tabulate, transcribe, transliterate, type