The transposition of initial or other sounds of words, usually by accident, as in a blushing crow for a crushing blow. Spoonerisms were coined around 1900 by the Reverend William Archibald Spooner (1844-1930) a kindly but nervous educationalist and Anglican clergyman who worked as a cleric and scholar serving as Dean and Warden of Oxford's New College spanning a carrer of over forty years.

It is said he once addressed a group of farmers as "ye noble tons of soil," queried after a university official by asking "Is the bean dizzy?" and admonished a student because he had "tasted two worms" and "hissed all my mystery lectures."

Spoonerisms have been used by the American humorist Colonel Stoopnagel in My Tale is Twisted,(1946) and Little Slack Bamboo and comprise areas of James Joyce's technique in Finnegan's Wake. Feghoots are vignettes ending in puns which are frequently Spooneristic and Isaac Asimov did quite a few.

Spoonerisms are fairly easy to come up with, here are a few simple guidelines:

    First, you take the two sounds from the beginning of two different words/syllables. --funny bone
    Next, interchange the two sounds to the other wordor syllable --bunny fone
    When writing them, make sure to spell the resulting words correctly -- bunny phone
    Finally, not all Spoonerisms will make sense; instead they may just sound strange or funny, often times a certain poetry can result.

More a slip of the tongue spoonerisms have phonetic resemblance to one another, as in slow and sneet (snow and sleet). They can also affect vowels, as in cuss and kiddle (kiss and cuddle), as well as, the final sounds of words and syllables: hass or grash (hash or grass). These spoonerisms give rise to evidence as to how speech is planned in the brain before uttered and also affect larger items, such as whole syllables and words: mouth in her food (food in her mouth), to gap the bridge (to bridge the gap).

More Spoonerisms

    Cattle ships and bruisers = Battle ships and cruisers
    Nosey little cook = Cosy little nook
    A blushing crow = A crushing blow
    Fighting a liar = Lighting a fire
    You hissed my mystery lecture = You missed my history lecture
    You've tasted two worms = You've wasted two terms
    Our shoving leopard = Our loving shepherd
    A half-warmed fish = A half-formed wish
    Is the bean dizzy? = Is the Dean busy?
    Know your blows = Blow your nose
    Go and shake a tower = Go and take a shower
    Tease my ears = Ease my tears
    Stop nicking your pose = Stop picking your nose
    Lack of pies = Pack of lies
    It's roaring with pain = It's pouring with rain
    Sealing the hick = Healing the sick
    Go help me sod = So help me God
    Pit nicking = Nit picking
    Disgusting bowel feast = Disgusting foul beast
    I'm a damp stealer = I'm a stamp dealer
    Hyperdemic nurdle = Hyperdermic needle
    Wave the sails = Save the whales
    I was chipping the flannel on the TV = I was flipping the channel on the TV
    Mad bunny = Bad money
    I'm shout of the hour = I'm out of the shower
    Lead of spite = Speed of light
    This is the pun fart = This is the fun part
    I hit my bunny phone = I hit my funny bone
    Flutter by = Butterfly
    Bedding Wells = Wedding Bells
    I must mend the sail = I must send the mail
    Cop porn = Popcorn
    It crawls through the fax = It falls through the cracks
    My zips are lipped = My lips are zipped
    Bat flattery = Flat battery
    Would you like a nasal hut? = Would you like a hazel nut?
    Belly jeans = Jelly beans
    Eye ball = Bye all
    Fight in your race = Right in your face
    Ready as a stock = Steady as a rock
    No tails = Toe nails
    Hiss and lear = Listen here
    back-asswords = ass backwards
    mood fart = food mart
    clot shock = shot clock
    fire truck = friar tuck
    sparking pot = parking spot
    larking pot = parking lot
    haystack=stay hack
    power surge = sower purge
    word math = mad worth
    word switch = sword witch
    scout troop = trout scoop
    foot prints = put fwints
    dain bramage = brain damage
    pull a rabbit out of a hat = habit out of a rat'
    quick trip = trick quip
Many many thanks to abiessu who has made several clever contributions! If you would like me to include one one of your favorites,/msg me and I'll add it spooner or later;)

Sources

Crackedcrosswords:
http://www.crackedcrosswords.com

xrefer :
http://www.xrefer.com