Here's a sizing guide and tips for finding your best fit:

-DVF is sized for the US market--larger than most Euro designers (Cavalli, Dolce Gabbana, Prada, etc.)

-UK/AUS size conversion is generally 'US size + 4' (I've done the math for you in the chart below--in inches & cm).  General EUR/IT sizing is also converted below.

-Special occasion dresses can run smaller than wrap/pull-on/shirt dress styles.  This is especially noticeable in the bust, so if you're a C cup or larger, I feel your pain and suggest that you either ask the seller for exact measurements or 'upsize' by a size.  That is, assuming that you don't want a dress that's (in the words of one of my favorite customers) 'porn star tight'. (-:

-Wrap dresses can be adjusted 1-2 inches either way; DVF experts recommend wrapping tightly--check out the article in my blog 'DogMom's Dish' on 'How to Tie a DVF Wrap Dress' (access via my About Me page below):

 http://members.ebay.com/ws/eBayISAPI.dll?ViewUserPage&userid=dogmom11

US              0       2       4       6       8      10     12       14
bust (inch)   32     33     34     35     36     37     38.5    40
waist           24     25     26     27     28     29     30.5    32
hips             34.5  35.5  36.5  37.5  38.5  39.5   41       42.5

UK/AUS    4       6       8       10      12     14     16      18
EUR/IT      34     36     38      40      42     44     46      48

bust (cm)    81.5 84      86.5   89     91.5   94     98     101.5
waist          61    63.5    66     68.5   71     73.5  77.5    81.5
hips            87.5 90       92.5  95     97.5  100   104     108