WordNet (r) 3.0 (2006):

spoonerism
    n 1: transposition of initial consonants in a pair of words

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "spoonerism":
   Irish bull, abuse of terms, acronym, acrostic, amphibologism,
   amphiboly, anacoluthon, anagram, avyayibhava, back formation, bull,
   calembour, catachresis, clipped word, compound, conjugate,
   construction, corruption, dvandva, dvigu, endocentric compound,
   equivocality, equivoque, exocentric compound, fluff,
   folk etymology, formation, grammatical error, hypercorrection,
   hyperform, jeu de mots, logogram, logogriph, malaprop, malapropism,
   marrowsky, metagram, mispronunciation, missaying, misusage,
   palindrome, paronomasia, paronym, play on words, pun, punning,
   solecism, tatpurusha, word form, wordplay